how to run fuzz target

[0xfocu5]

I noticed these from readme
mkdir afl_in
cargo build --bin gen_fuzz
./target/debug/gen_fuzz >./afl_in/seed

cargo afl build --features="afl-fuzz" --bin fuzz_target_afl
cargo afl fuzz -i afl_in -o afl_out target/debug/fuzz_target_afl

but I got a crash , how can i run fuzz succeedly.

thread 'main' panicked at 'We own the rx.: ()', fuzz/src/lib.rs:47:29
stack backtrace:
   0: rust_begin_unwind
             at /rustc/5680fa18feaa87f3ff04063800aec256c3d4b4be/library/std/src/panicking.rs:593:5
   1: core::panicking::panic_fmt
             at /rustc/5680fa18feaa87f3ff04063800aec256c3d4b4be/library/core/src/panicking.rs:67:14
   2: core::result::unwrap_failed
             at /rustc/5680fa18feaa87f3ff04063800aec256c3d4b4be/library/core/src/result.rs:1651:5
   3: core::result::Result<T,E>::expect
             at /rustc/5680fa18feaa87f3ff04063800aec256c3d4b4be/library/core/src/result.rs:1033:23
   4: <aleph_bft_fuzz::MockSpawner as aleph_bft_types::tasks::SpawnHandle>::spawn_essential::{{closure}}
             at ./src/lib.rs:47:13
   5: tokio::runtime::task::core::Core<T,S>::poll::{{closure}}
             at /home/vuln/.cargo/registry/src/index.crates.io-6f17d22bba15001f/tokio-1.35.1/src/runtime/task/core.rs:328:17
   6: tokio::loom::std::unsafe_cell::UnsafeCell<T>::with_mut
             at /home/vuln/.cargo/registry/src/index.crates.io-6f17d22bba15001f/tokio-1.35.1/src/loom/std/unsafe_cell.rs:16:9
   7: tokio::runtime::task::core::Core<T,S>::poll
             at /home/vuln/.cargo/registry/src/index.crates.io-6f17d22bba15001f/tokio-1.35.1/src/runtime/task/core.rs:317:13
   8: tokio::runtime::task::harness::poll_future::{{closure}}
             at /home/vuln/.cargo/registry/src/index.crates.io-6f17d22bba15001f/tokio-1.35.1/src/runtime/task/harness.rs:485:19
   9: <core::panic::unwind_safe::AssertUnwindSafe<F> as core::ops::function::FnOnce<()>>::call_once
             at /rustc/5680fa18feaa87f3ff04063800aec256c3d4b4be/library/core/src/panic/unwind_safe.rs:271:9
  10: std::panicking::try::do_call
             at /rustc/5680fa18feaa87f3ff04063800aec256c3d4b4be/library/std/src/panicking.rs:500:40
  11: __rust_try
  12: std::panicking::try
             at /rustc/5680fa18feaa87f3ff04063800aec256c3d4b4be/library/std/src/panicking.rs:464:19
  13: std::panic::catch_unwind
             at /rustc/5680fa18feaa87f3ff04063800aec256c3d4b4be/library/std/src/panic.rs:142:14
  14: tokio::runtime::task::harness::poll_future
             at /home/vuln/.cargo/registry/src/index.crates.io-6f17d22bba15001f/tokio-1.35.1/src/runtime/task/harness.rs:473:18
  15: tokio::runtime::task::harness::Harness<T,S>::poll_inner
             at /home/vuln/.cargo/registry/src/index.crates.io-6f17d22bba15001f/tokio-1.35.1/src/runtime/task/harness.rs:208:27
  16: tokio::runtime::task::harness::Harness<T,S>::poll
             at /home/vuln/.cargo/registry/src/index.crates.io-6f17d22bba15001f/tokio-1.35.1/src/runtime/task/harness.rs:153:15
  17: tokio::runtime::task::raw::poll
             at /home/vuln/.cargo/registry/src/index.crates.io-6f17d22bba15001f/tokio-1.35.1/src/runtime/task/raw.rs:271:5
  18: tokio::runtime::task::raw::RawTask::poll
             at /home/vuln/.cargo/registry/src/index.crates.io-6f17d22bba15001f/tokio-1.35.1/src/runtime/task/raw.rs:201:18
  19: tokio::runtime::task::LocalNotified<S>::run
             at /home/vuln/.cargo/registry/src/index.crates.io-6f17d22bba15001f/tokio-1.35.1/src/runtime/task/mod.rs:416:9
  20: tokio::runtime::scheduler::current_thread::CoreGuard::block_on::{{closure}}::{{closure}}
             at /home/vuln/.cargo/registry/src/index.crates.io-6f17d22bba15001f/tokio-1.35.1/src/runtime/scheduler/current_thread/mod.rs:706:25
  21: tokio::runtime::coop::with_budget
             at /home/vuln/.cargo/registry/src/index.crates.io-6f17d22bba15001f/tokio-1.35.1/src/runtime/coop.rs:107:5
  22: tokio::runtime::coop::budget
             at /home/vuln/.cargo/registry/src/index.crates.io-6f17d22bba15001f/tokio-1.35.1/src/runtime/coop.rs:73:5
  23: tokio::runtime::scheduler::current_thread::Context::run_task::{{closure}}
             at /home/vuln/.cargo/registry/src/index.crates.io-6f17d22bba15001f/tokio-1.35.1/src/runtime/scheduler/current_thread/mod.rs:343:43
  24: tokio::runtime::scheduler::current_thread::Context::enter
             at /home/vuln/.cargo/registry/src/index.crates.io-6f17d22bba15001f/tokio-1.35.1/src/runtime/scheduler/current_thread/mod.rs:410:19
  25: tokio::runtime::scheduler::current_thread::Context::run_task
             at /home/vuln/.cargo/registry/src/index.crates.io-6f17d22bba15001f/tokio-1.35.1/src/runtime/scheduler/current_thread/mod.rs:343:23
  26: tokio::runtime::scheduler::current_thread::CoreGuard::block_on::{{closure}}
             at /home/vuln/.cargo/registry/src/index.crates.io-6f17d22bba15001f/tokio-1.35.1/src/runtime/scheduler/current_thread/mod.rs:705:35
  27: tokio::runtime::scheduler::current_thread::CoreGuard::enter::{{closure}}
             at /home/vuln/.cargo/registry/src/index.crates.io-6f17d22bba15001f/tokio-1.35.1/src/runtime/scheduler/current_thread/mod.rs:743:68
  28: tokio::runtime::context::scoped::Scoped<T>::set
             at /home/vuln/.cargo/registry/src/index.crates.io-6f17d22bba15001f/tokio-1.35.1/src/runtime/context/scoped.rs:40:9
  29: tokio::runtime::context::set_scheduler::{{closure}}
             at /home/vuln/.cargo/registry/src/index.crates.io-6f17d22bba15001f/tokio-1.35.1/src/runtime/context.rs:176:26
  30: std::thread::local::LocalKey<T>::try_with
             at /rustc/5680fa18feaa87f3ff04063800aec256c3d4b4be/library/std/src/thread/local.rs:270:16
  31: std::thread::local::LocalKey<T>::with
             at /rustc/5680fa18feaa87f3ff04063800aec256c3d4b4be/library/std/src/thread/local.rs:246:9
  32: tokio::runtime::context::set_scheduler
             at /home/vuln/.cargo/registry/src/index.crates.io-6f17d22bba15001f/tokio-1.35.1/src/runtime/context.rs:176:9
  33: tokio::runtime::scheduler::current_thread::CoreGuard::enter
             at /home/vuln/.cargo/registry/src/index.crates.io-6f17d22bba15001f/tokio-1.35.1/src/runtime/scheduler/current_thread/mod.rs:743:27
  34: tokio::runtime::scheduler::current_thread::CoreGuard::block_on
             at /home/vuln/.cargo/registry/src/index.crates.io-6f17d22bba15001f/tokio-1.35.1/src/runtime/scheduler/current_thread/mod.rs:652:19
  35: tokio::runtime::scheduler::current_thread::CurrentThread::block_on::{{closure}}
             at /home/vuln/.cargo/registry/src/index.crates.io-6f17d22bba15001f/tokio-1.35.1/src/runtime/scheduler/current_thread/mod.rs:175:28
  36: tokio::runtime::context::runtime::enter_runtime
             at /home/vuln/.cargo/registry/src/index.crates.io-6f17d22bba15001f/tokio-1.35.1/src/runtime/context/runtime.rs:65:16
  37: tokio::runtime::scheduler::current_thread::CurrentThread::block_on
             at /home/vuln/.cargo/registry/src/index.crates.io-6f17d22bba15001f/tokio-1.35.1/src/runtime/scheduler/current_thread/mod.rs:167:9
  38: tokio::runtime::runtime::Runtime::block_on
             at /home/vuln/.cargo/registry/src/index.crates.io-6f17d22bba15001f/tokio-1.35.1/src/runtime/runtime.rs:348:47
  39: aleph_bft_fuzz::fuzz
             at ./src/lib.rs:514:5
  40: check::run
             at ./src/check.rs:8:5
  41: check::main
             at ./src/check.rs:30:5
  42: core::ops::function::FnOnce::call_once
             at /rustc/5680fa18feaa87f3ff04063800aec256c3d4b4be/library/core/src/ops/function.rs:250:5
note: Some details are omitted, run with `RUST_BACKTRACE=full` for a verbose backtrace.