How to solve this issue " Downlevel flags DownlevelFlags(INDIRECT_EXECUTION)" for IOS simulator?

[videni]

Hi, Can anybody give me a hand please? I am new to WGPU, I think it may take me 10 years to solve this issue myself, please check this demo

* am I framebufferOnly enabled? true
/Users/vidy/Library/Developer/CoreSimulator/Devices/F1C874E7-2311-4009-A6AD-AD693D675EFE/data/Containers/Bundle/Application/E4D06D5D-3F6F-4DFF-8665-67A9FA7C4D02/VelloDemo.app
AppSurface_create, maximum frames: 60
  �[2m2025-01-23T07:30:13.101101Z�[0m �[32m INFO�[0m �[1;32mwgpu_core::instance�[0m�[32m: �[32mAdapter AdapterInfo { name: "Apple iOS simulator GPU", vendor: 0, device: 0, device_type: DiscreteGpu, driver: "", driver_info: "", backend: Metal }�[0m
    �[2;3mat�[0m /Users/vidy/.cargo/registry/src/index.crates.io-6f17d22bba15001f/wgpu-core-23.0.1/src/instance.rs:382

Using Apple iOS simulator GPU (Metal)
[/Users/vidy/Workspace/wgpu-in-app/app-surface/src/lib.rs:248:5] adapter.features() = Features(
    DEPTH32FLOAT_STENCIL8 | TEXTURE_COMPRESSION_ETC2 | TEXTURE_COMPRESSION_ASTC | SHADER_F16 | BGRA8UNORM_STORAGE | TEXTURE_FORMAT_16BIT_NORM | TEXTURE_ADAPTER_SPECIFIC_FORMAT_FEATURES | MAPPABLE_PRIMARY_BUFFERS | PUSH_CONSTANTS | ADDRESS_MODE_CLAMP_TO_ZERO | POLYGON_MODE_LINE | VERTEX_WRITABLE_STORAGE | CLEAR_TEXTURE | SHADER_PRIMITIVE_INDEX | DUAL_SOURCE_BLENDING,
)
  �[2m2025-01-23T07:30:13.102168Z�[0m �[33m WARN�[0m �[1;33mwgpu_core::instance�[0m�[33m: �[33mMissing downlevel flags: DownlevelFlags(INDIRECT_EXECUTION | BASE_VERTEX | CUBE_ARRAY_TEXTURES | COMPARISON_SAMPLERS)
The underlying API or device in use does not support enough features to be a fully compliant implementation of WebGPU. A subset of the features can still be used. If you are running this program on native and not in a browser and wish to limit the features you use to the supported subset, call Adapter::downlevel_properties or Device::downlevel_properties to get a listing of the features the current platform supports.�[0m
    �[2;3mat�[0m /Users/vidy/.cargo/registry/src/index.crates.io-6f17d22bba15001f/wgpu-core-23.0.1/src/instance.rs:609

  �[2m2025-01-23T07:30:13.102179Z�[0m �[33m WARN�[0m �[1;33mwgpu_core::instance�[0m�[33m: �[33mDownlevelCapabilities {
    flags: DownlevelFlags(
        COMPUTE_SHADERS | FRAGMENT_WRITABLE_STORAGE | READ_ONLY_DEPTH_STENCIL | NON_POWER_OF_TWO_MIPMAPPED_TEXTURES | INDEPENDENT_BLEND | VERTEX_STORAGE | ANISOTROPIC_FILTERING | FRAGMENT_STORAGE | MULTISAMPLED_SHADING | DEPTH_TEXTURE_AND_BUFFER_COPIES | WEBGPU_TEXTURE_FORMAT_SUPPORT | BUFFER_BINDINGS_NOT_16_BYTE_ALIGNED | UNRESTRICTED_INDEX_BUFFER | FULL_DRAW_INDEX_UINT32 | DEPTH_BIAS_CLAMP | VIEW_FORMATS | UNRESTRICTED_EXTERNAL_TEXTURE_COPIES | SURFACE_VIEW_FORMATS | NONBLOCKING_QUERY_RESOLVE | VERTEX_AND_INSTANCE_INDEX_RESPECTS_RESPECTIVE_FIRST_VALUE_IN_INDIRECT_DRAW,
    ),
    limits: DownlevelLimits,
    shader_model: Sm5,
}�[0m
    �[2;3mat�[0m /Users/vidy/.cargo/registry/src/index.crates.io-6f17d22bba15001f/wgpu-core-23.0.1/src/instance.rs:614

  �[2m2025-01-23T07:30:13.102210Z�[0m �[33m WARN�[0m �[1;33mwgpu_core::instance�[0m�[33m: �[33mFeature MAPPABLE_PRIMARY_BUFFERS enabled on a discrete gpu. This is a massive performance footgun and likely not what you wanted�[0m
    �[2;3mat�[0m /Users/vidy/.cargo/registry/src/index.crates.io-6f17d22bba15001f/wgpu-core-23.0.1/src/instance.rs:623

App_render Rectangle { x: 0.0, y: 0.0, width: 820.0, height: 1131.0 }
Vello demo - splash_with_tiger
Parsed svg Ghostscript Tiger in 7.186458ms
Encoded svg Ghostscript Tiger in 1.74125ms
Initialising in parallel using 9 threads
Thread Performance Checker: Thread running at User-interactive quality-of-service class waiting on a lower QoS thread running at Default quality-of-service class. Investigate ways to avoid priority inversions
PID: 11793, TID: 29356439
Backtrace
=================================================================
0   VelloDemo.debug.dylib               0x000000010849cbc4 _ZN3std6thread12park_timeout17he7c98b63676abbc0E + 212
1   VelloDemo.debug.dylib               0x000000010765a2d8 _ZN3std4sync4mpmc7context7Context10wait_until17h0222a4e8244fc8d6E + 712
2   VelloDemo.debug.dylib               0x00000001075ee134 _ZN3std4sync4mpmc4list16Channel$LT$T$GT$4recv28_$u7b$$u7b$closure$u7d$$u7d$17h611ac0f9b56772cbE + 268
3   VelloDemo.debug.dylib               0x000000010765ab84 _ZN3std4sync4mpmc7context7Context4with28_$u7b$$u7b$closure$u7d$$u7d$17h2e4cd832900b910dE + 516
4   VelloDemo.debug.dylib               0x000000010760edb4 _ZN3std6thread5local17LocalKey$LT$T$GT$8try_with17h0cfc5334daf8bf05E + 176
5   VelloDemo.debug.dylib               0x000000010765a36c _ZN3std4sync4mpmc7context7Context4with17h0b158877dbf494a7E + 52
6   VelloDemo.debug.dylib               0x00000001075edf44 _ZN3std4sync4mpmc4list16Channel$LT$T$GT$4recv17h8dc17ded2a2cab14E + 372
7   VelloDemo.debug.dylib               0x00000001075fc0dc _ZN3std4sync4mpmc17Receiver$LT$T$GT$13recv_deadline17hc8026e6fcdf49846E + 180
8   VelloDemo.debug.dylib               0x00000001075fbfc8 _ZN3std4sync4mpmc17Receiver$LT$T$GT$12recv_timeout17h16db2bfddb491f8eE + 184
9   VelloDemo.debug.dylib               0x0000000107631188 _ZN3std4sync4mpsc17Receiver$LT$T$GT$12recv_timeout17h544642744a66ded3E + 32
10  VelloDemo.debug.dylib               0x000000010761f950 _ZN6scenes3svg15svg_function_of28_$u7b$$u7b$closure$u7d$$u7d$17h0bad5c956b3739f2E + 960
11  VelloDemo.debug.dylib               0x0000000107644e3c _ZN6scenes11test_scenes5impls17splash_with_tiger28_$u7b$$u7b$closure$u7d$$u7d$17hbe3332d6ec5113baE + 56
12  VelloDemo.debug.dylib               0x00000001076463bc _ZN39_$LT$F$u20$as$u20$scenes..TestScene$GT$6render17hd00ba79f43d2c2c8E + 40
13  VelloDemo.debug.dylib               0x0000000107351dd8 App_render + 992
14  VelloDemo.debug.dylib               0x000000010734ebec $s9VelloDemo19MetalViewControllerC13viewDidAppearyySbF + 1548
15  VelloDemo.debug.dylib               0x000000010734ed24 $s9VelloDemo19MetalViewControllerC13viewDidAppearyySbFTo + 56
16  UIKitCore                           0x000000018536c298 -[UIViewController _setViewAppearState:isAnimating:] + 1116
17  UIKitCore                           0x000000018536c71c __52-[UIViewController _setViewAppearState:isAnimating:]_block_invoke_2 + 164
18  UIKitCore                           0x000000018536c5bc __52-[UIViewController _setViewAppearState:isAnimating:]_block_invoke + 160
19  CoreFoundation                      0x000000018041f558 __NSARRAY_IS_CALLING_OUT_TO_A_BLOCK__ + 16
20  CoreFoundation                      0x00000001804ffce8 -[__NSSingleObjectArrayI enumerateObjectsWithOptions:usingBlock:] + 88
21  UIKitCore                           0x000000018536c3e0 -[UIViewController _setViewAppearState:isAnimating:] + 1444
22  UIKitCore                           0x000000018536cd00 -[UIViewController __viewDidAppear:] + 164
23  UIKitCore                           0x000000018536d020 -[UIViewController _endAppearanceTransition:] + 200
24  UIKitCore                           0x0000000185277b6c __48-[UIPresentationController transitionDidFinish:]_block_invoke + 100
25  UIKitCore                           0x0000000185fead08 -[_UIAfterCACommitBlock run] + 64
26  UIKitCore                           0x0000000185feb118 -[_UIAfterCACommitQueue flush] + 160
27  UIKitCore                           0x0000000185ae4ee8 _runAfterCACommitDeferredBlocks + 256
28  UIKitCore                           0x0000000185ad6b68 _cleanUpAfterCAFlushAndRunDeferredBlocks + 76
29  UIKitCore                           0x0000000185ad6c30 _UIApplicationFlushCATransaction + 68
30  UIKitCore                           0x0000000185a07ccc __setupUpdateSequence_block_invoke_2 + 352
31  UIKitCore                           0x000000018505d28c _UIUpdateSequenceRun + 76
32  UIKitCore                           0x0000000185a07670 schedulerStepScheduledMainSection + 168
33  UIKitCore                           0x0000000185a06aa8 runloopSourceCallback + 80
34  CoreFoundation                      0x000000018041b7c4 __CFRUNLOOP_IS_CALLING_OUT_TO_A_SOURCE0_PERFORM_FUNCTION__ + 24
35  CoreFoundation                      0x000000018041b70c __CFRunLoopDoSource0 + 172
36  CoreFoundation                      0x000000018041aecc __CFRunLoopDoSources0 + 324
37  CoreFoundation                      0x00000001804153b4 __CFRunLoopRun + 788
38  CoreFoundation                      0x0000000180414c24 CFRunLoopRunSpecific + 552
39  GraphicsServices                    0x000000019020ab10 GSEventRunModal + 160
40  UIKitCore                           0x0000000185ad82fc -[UIApplication _run] + 796
41  UIKitCore                           0x0000000185adc4f4 UIApplicationMain + 124
42  SwiftUI                             0x00000001d290b41c $s7SwiftUI17KitRendererCommon33_ACC2C5639A7D76F611E170E831FCA491LLys5NeverOyXlXpFAESpySpys4Int8VGSgGXEfU_ + 164
43  SwiftUI                             0x00000001d290b144 $s7SwiftUI6runAppys5NeverOxAA0D0RzlF + 84
44  SwiftUI                             0x00000001d266bef4 $s7SwiftUI3AppPAAE4mainyyFZ + 148
45  VelloDemo.debug.dylib               0x0000000107350bdc $s9VelloDemo0aB3AppV5$mainyyFZ + 40
46  VelloDemo.debug.dylib               0x0000000107350c8c __debug_main_executable_dylib_entry_point + 12
[/Users/vidy/Workspace/wgpu-in-app/app-surface/src/lib.rs:112:9] &frame.texture = Texture {
    context: ContextWgpuCore {
        type: "Native",
    },
    data: Any { .. },
    descriptor: TextureDescriptor {
        label: None,
        size: (
            1640,
            2360,
            1,
        ),
        mip_level_count: 1,
        sample_count: 1,
        dimension: D2,
        format: Bgra8UnormSrgb,
        usage: TextureUsages(
            RENDER_ATTACHMENT,
        ),
        view_formats: [],
    },
}
  �[2m2025-01-23T07:30:13.464386Z�[0m �[31mERROR�[0m �[1;31mwgpu::backend::wgpu_core�[0m�[31m: �[31mHandling wgpu errors as fatal by default�[0m
    �[2;3mat�[0m /Users/vidy/.cargo/registry/src/index.crates.io-6f17d22bba15001f/wgpu-23.0.1/src/backend/wgpu_core.rs:1196

thread '<unnamed>' panicked at /Users/vidy/.cargo/registry/src/index.crates.io-6f17d22bba15001f/wgpu-23.0.1/src/backend/wgpu_core.rs:1196:18:
wgpu error: Validation Error

Caused by:
  In Device::create_buffer, label = 'vello.reduced_buf'
    Downlevel flags DownlevelFlags(INDIRECT_EXECUTION) are required but not supported on the device.
This is not an invalid use of WebGPU: the underlying API or device does not support enough features to be a fully compliant implementation. A subset of the features can still be used. If you are running this program on native and not in a browser and wish to work around this issue, call Adapter::downlevel_properties or Device::downlevel_properties to get a listing of the features the current platform supports.


stack backtrace:
   0: rust_begin_unwind
             at ./rustc/9fc6b43126469e3858e2fe86cafb4f0fd5068869/library/std/src/panicking.rs:665:5
   1: core::panicking::panic_fmt
             at ./rustc/9fc6b43126469e3858e2fe86cafb4f0fd5068869/library/core/src/panicking.rs:76:14
   2: wgpu::backend::wgpu_core::default_error_handler
             at ./Users/vidy/.cargo/registry/src/index.crates.io-6f17d22bba15001f/wgpu-23.0.1/src/backend/wgpu_core.rs:3050:5
   3: wgpu::backend::wgpu_core::ErrorSinkRaw::handle_error
             at ./Users/vidy/.cargo/registry/src/index.crates.io-6f17d22bba15001f/wgpu-23.0.1/src/backend/wgpu_core.rs:3034:21
   4: wgpu::backend::wgpu_core::ContextWgpuCore::handle_error_inner
             at ./Users/vidy/.cargo/registry/src/index.crates.io-6f17d22bba15001f/wgpu-23.0.1/src/backend/wgpu_core.rs:299:9
   5: wgpu::backend::wgpu_core::ContextWgpuCore::handle_error
             at ./Users/vidy/.cargo/registry/src/index.crates.io-6f17d22bba15001f/wgpu-23.0.1/src/backend/wgpu_core.rs:311:9
   6: <wgpu::backend::wgpu_core::ContextWgpuCore as wgpu::context::Context>::device_create_buffer
             at ./Users/vidy/.cargo/registry/src/index.crates.io-6f17d22bba15001f/wgpu-23.0.1/src/backend/wgpu_core.rs:1196:13
   7: <T as wgpu::context::DynContext>::device_create_buffer
             at ./Users/vidy/.cargo/registry/src/index.crates.io-6f17d22bba15001f/wgpu-23.0.1/src/context.rs:1583:20
   8: wgpu::api::device::Device::create_buffer
             at ./Users/vidy/.cargo/registry/src/index.crates.io-6f17d22bba15001f/wgpu-23.0.1/src/api/device.rs:235:20
   9: vello::wgpu_engine::ResourcePool::get_buf
             at ./Users/vidy/.cargo/git/checkouts/vello-597be072a8b1ddcb/ef1c68e/vello/src/wgpu_engine.rs:949:9
  10: vello::wgpu_engine::TransientBindMap::create_bind_group
             at ./Users/vidy/.cargo/git/checkouts/vello-597be072a8b1ddcb/ef1c68e/vello/src/wgpu_engine.rs:1064:39
  11: vello::wgpu_engine::WgpuEngine::run_recording
             at ./Users/vidy/.cargo/git/checkouts/vello-597be072a8b1ddcb/ef1c68e/vello/src/wgpu_engine.rs:539:46
  12: vello::Renderer::render_to_texture
             at ./Users/vidy/.cargo/git/checkouts/vello-597be072a8b1ddcb/ef1c68e/vello/src/lib.rs:478:9
  13: App_render
             at ./Users/vidy/Workspace/vello-ios/rust/src/lib.rs:154:5
  14: <unknown>
             at ./Users/vidy/Workspace/vello-ios/ios/VelloDemo/MetalViewController.swift:52:9
  15: <unknown>
  16: -[UIViewController _setViewAppearState:isAnimating:]
  17: ___52-[UIViewController _setViewAppearState:isAnimating:]_block_invoke_2
  18: ___52-[UIViewController _setViewAppearState:isAnimating:]_block_invoke
  19: ___NSARRAY_IS_CALLING_OUT_TO_A_BLOCK__
  20: -[__NSSingleObjectArrayI enumerateObjectsWithOptions:usingBlock:]
  21: -[UIViewController _setViewAppearState:isAnimating:]
  22: -[UIViewController __viewDidAppear:]
  23: -[UIViewController _endAppearanceTransition:]
  24: ___48-[UIPresentationController transitionDidFinish:]_block_invoke
  25: -[_UIAfterCACommitBlock run]
  26: -[_UIAfterCACommitQueue flush]
  27: __runAfterCACommitDeferredBlocks
  28: __cleanUpAfterCAFlushAndRunDeferredBlocks
  29: __UIApplicationFlushCATransaction
  30: ___setupUpdateSequence_block_invoke_2
  31: __UIUpdateSequenceRun
  32: _schedulerStepScheduledMainSection
  33: _runloopSourceCallback
  34: ___CFRUNLOOP_IS_CALLING_OUT_TO_A_SOURCE0_PERFORM_FUNCTION__
  35: ___CFRunLoopDoSource0
  36: ___CFRunLoopDoSources0
  37: ___CFRunLoopRun
  38: _CFRunLoopRunSpecific
  39: _GSEventRunModal
  40: -[UIApplication _run]
  41: _UIApplicationMain
  42: _$s7SwiftUI17KitRendererCommon33_ACC2C5639A7D76F611E170E831FCA491LLys5NeverOyXlXpFAESpySpys4Int8VGSgGXEfU_
  43: _$s7SwiftUI6runAppys5NeverOxAA0D0RzlF
  44: _$s7SwiftUI3AppPAAE4mainyyFZ
  45: <unknown>
  46: <unknown>
             at ./Users/vidy/Workspace/vello-ios/ios/VelloDemo/VelloDemoApp.swift:12:8
note: Some details are omitted, run with `RUST_BACKTRACE=full` for a verbose backtrace.
thread '<unnamed>' panicked at core/src/panicking.rs:223:5:
panic in a function that cannot unwind
stack backtrace:
   0:        0x1084b33c4 - std::backtrace_rs::backtrace::libunwind::trace::hca517c2a2f3232d7
                               at /rustc/9fc6b43126469e3858e2fe86cafb4f0fd5068869/library/std/src/../../backtrace/src/backtrace/libunwind.rs:116:5
   1:        0x1084b33c4 - std::backtrace_rs::backtrace::trace_unsynchronized::hd7d769e02b4ac1b7
                               at /rustc/9fc6b43126469e3858e2fe86cafb4f0fd5068869/library/std/src/../../backtrace/src/backtrace/mod.rs:66:5
   2:        0x1084b33c4 - std::sys::backtrace::_print_fmt::h551e35a2316a59a7
                               at /rustc/9fc6b43126469e3858e2fe86cafb4f0fd5068869/library/std/src/sys/backtrace.rs:66:9
   3:        0x1084b33c4 - <std::sys::backtrace::BacktraceLock::print::DisplayBacktrace as core::fmt::Display>::fmt::h026fb7f6a7f1ea39
                               at /rustc/9fc6b43126469e3858e2fe86cafb4f0fd5068869/library/std/src/sys/backtrace.rs:39:26
   4:        0x1084f2410 - core::fmt::rt::Argument::fmt::hbbdcec2d9d076bc0
                               at /rustc/9fc6b43126469e3858e2fe86cafb4f0fd5068869/library/core/src/fmt/rt.rs:177:76
   5:        0x1084f2410 - core::fmt::write::h91d8d0cf45debf6a
                               at /rustc/9fc6b43126469e3858e2fe86cafb4f0fd5068869/library/core/src/fmt/mod.rs:1189:21
   6:        0x1084a8594 - std::io::Write::write_fmt::h170ebb15403e2ed9
                               at /rustc/9fc6b43126469e3858e2fe86cafb4f0fd5068869/library/std/src/io/mod.rs:1884:15
   7:        0x1084b3278 - std::sys::backtrace::BacktraceLock::print::h1c5c12d59c277afd
                               at /rustc/9fc6b43126469e3858e2fe86cafb4f0fd5068869/library/std/src/sys/backtrace.rs:42:9
   8:        0x1084b55e0 - std::panicking::default_hook::{{closure}}::h3fa22478e40098bd
                               at /rustc/9fc6b43126469e3858e2fe86cafb4f0fd5068869/library/std/src/panicking.rs:268:22
   9:        0x1084b541c - std::panicking::default_hook::h929560e7fdb6dec1
                               at /rustc/9fc6b43126469e3858e2fe86cafb4f0fd5068869/library/std/src/panicking.rs:295:9
  10:        0x1084b5e6c - std::panicking::rust_panic_with_hook::h74f0aa88ce9d76f1
                               at /rustc/9fc6b43126469e3858e2fe86cafb4f0fd5068869/library/std/src/panicking.rs:801:13
  11:        0x1084b5ab8 - std::panicking::begin_panic_handler::{{closure}}::hd7f7ba893f6d048a
                               at /rustc/9fc6b43126469e3858e2fe86cafb4f0fd5068869/library/std/src/panicking.rs:667:13
  12:        0x1084b3888 - std::sys::backtrace::__rust_end_short_backtrace::hb30a0dde357a9afa
                               at /rustc/9fc6b43126469e3858e2fe86cafb4f0fd5068869/library/std/src/sys/backtrace.rs:170:18
  13:        0x1084b5798 - rust_begin_unwind
                               at /rustc/9fc6b43126469e3858e2fe86cafb4f0fd5068869/library/std/src/panicking.rs:665:5
  14:        0x108540868 - core::panicking::panic_nounwind_fmt::runtime::h9a065bc8d9a43faa
                               at /rustc/9fc6b43126469e3858e2fe86cafb4f0fd5068869/library/core/src/panicking.rs:119:22
  15:        0x108540868 - core::panicking::panic_nounwind_fmt::he9af3757db449dbb
                               at /rustc/9fc6b43126469e3858e2fe86cafb4f0fd5068869/library/core/src/intrinsics/mod.rs:3535:9
  16:        0x1085408e0 - core::panicking::panic_nounwind::h5913f439a043d9da
                               at /rustc/9fc6b43126469e3858e2fe86cafb4f0fd5068869/library/core/src/panicking.rs:223:5
  17:        0x108540a58 - core::panicking::panic_cannot_unwind::h5d7baa6fc3483b98
                               at /rustc/9fc6b43126469e3858e2fe86cafb4f0fd5068869/library/core/src/panicking.rs:315:5
  18:        0x107352190 - App_render
                               at /Users/vidy/Workspace/vello-ios/rust/src/lib.rs:89:1
  19:        0x10734ebec - <unknown>
                               at /Users/vidy/Workspace/vello-ios/ios/VelloDemo/MetalViewController.swift:52:9
  20:        0x10734ed24 - <unknown>
  21:        0x18536c298 - -[UIViewController _setViewAppearState:isAnimating:]
  22:        0x18536c71c - ___52-[UIViewController _setViewAppearState:isAnimating:]_block_invoke_2
  23:        0x18536c5bc - ___52-[UIViewController _setViewAppearState:isAnimating:]_block_invoke
  24:        0x18041f558 - ___NSARRAY_IS_CALLING_OUT_TO_A_BLOCK__
  25:        0x1804ffce8 - -[__NSSingleObjectArrayI enumerateObjectsWithOptions:usingBlock:]
  26:        0x18536c3e0 - -[UIViewController _setViewAppearState:isAnimating:]
  27:        0x18536cd00 - -[UIViewController __viewDidAppear:]
  28:        0x18536d020 - -[UIViewController _endAppearanceTransition:]
  29:        0x185277b6c - ___48-[UIPresentationController transitionDidFinish:]_block_invoke
  30:        0x185fead08 - -[_UIAfterCACommitBlock run]
  31:        0x185feb118 - -[_UIAfterCACommitQueue flush]
  32:        0x185ae4ee8 - __runAfterCACommitDeferredBlocks
  33:        0x185ad6b68 - __cleanUpAfterCAFlushAndRunDeferredBlocks
  34:        0x185ad6c30 - __UIApplicationFlushCATransaction
  35:        0x185a07ccc - ___setupUpdateSequence_block_invoke_2
  36:        0x18505d28c - __UIUpdateSequenceRun
  37:        0x185a07670 - _schedulerStepScheduledMainSection
  38:        0x185a06aa8 - _runloopSourceCallback
  39:        0x18041b7c4 - ___CFRUNLOOP_IS_CALLING_OUT_TO_A_SOURCE0_PERFORM_FUNCTION__
  40:        0x18041b70c - ___CFRunLoopDoSource0
  41:        0x18041aecc - ___CFRunLoopDoSources0
  42:        0x1804153b4 - ___CFRunLoopRun
  43:        0x180414c24 - _CFRunLoopRunSpecific
  44:        0x19020ab10 - _GSEventRunModal
  45:        0x185ad82fc - -[UIApplication _run]
  46:        0x185adc4f4 - _UIApplicationMain
  47:        0x1d290b41c - _$s7SwiftUI17KitRendererCommon33_ACC2C5639A7D76F611E170E831FCA491LLys5NeverOyXlXpFAESpySpys4Int8VGSgGXEfU_
  48:        0x1d290b144 - _$s7SwiftUI6runAppys5NeverOxAA0D0RzlF
  49:        0x1d266bef4 - _$s7SwiftUI3AppPAAE4mainyyFZ
  50:        0x107350bdc - <unknown>
  51:        0x107350c8c - <unknown>
                               at /Users/vidy/Workspace/vello-ios/ios/VelloDemo/VelloDemoApp.swift:12:8
thread caused non-unwinding panic. aborting.
Can't show file for stack frame : <DBGLLDBStackFrame: 0x358f6c580> - stackNumber:3 - name:std::sys::pal::unix::abort_internal::hef23a7f1fbafab72. The file path does not exist on the file system: /rustc/9fc6b43126469e3858e2fe86cafb4f0fd5068869/library/std/src/sys/pal/unix/mod.rs

Can't show file for stack frame : <DBGLLDBStackFrame: 0x35a7148f0> - stackNumber:11 - name:core::panicking::panic_cannot_unwind::h5d7baa6fc3483b98. The file path does not exist on the file system: /rustc/9fc6b43126469e3858e2fe86cafb4f0fd5068869/library/core/src/panicking.rsCan't show file for stack frame : <DBGLLDBStackFrame: 0x350a16300> - stackNumber:10 - name:core::panicking::panic_nounwind::h5913f439a043d9da. The file path does not exist on the file system: /rustc/9fc6b43126469e3858e2fe86cafb4f0fd5068869/library/core/src/panicking.rsCan't show file for stack frame : <DBGLLDBStackFrame: 0x358f6c7e0> - stackNumber:6 - name:std::sys::backtrace::__rust_end_short_backtrace::hb30a0dde357a9afa. The file path does not exist on the file system: /rustc/9fc6b43126469e3858e2fe86cafb4f0fd5068869/library/std/src/sys/backtrace.rs

[cwfitzgerald]

I don't think you can - the ios simulator is very limited in what it can support - I've heard a lot of bad things about it. You're trying to create a buffer with usage INDIRECT, but wgpu is detected the device doesn't support indirect draws.