feat(driver): multishot op

[Berrysoft]

Related: #104

[Copilot]

Pull request overview

This pull request implements multishot opcode support for io_uring operations, addressing issue #104. Multishot operations allow a single submission to generate multiple completion events, which is useful for operations like reading multiple buffers or receiving multiple network packets without resubmitting the operation each time.

Changes:

• Adds three new multishot operations: ReadMultiAt, ReadMulti, and RecvMulti that can produce multiple completion results from a single submission
• Implements a fallback mechanism via create_entry_fallback() to gracefully handle unsupported opcodes by falling back to single-shot operations
• Introduces pop_multishot() API to retrieve intermediate results from multishot operations before the final completion

Reviewed changes

Copilot reviewed 11 out of 11 changed files in this pull request and generated 6 comments.

Show a summary per file

File	Description
compio-driver/tests/file.rs	Adds test cases for multishot read and recv operations, including new test helper push_and_wait_multi
compio-driver/src/sys/stub/mod.rs	Provides stub implementation of pop_multishot returning None
compio-driver/src/sys/poll/mod.rs	Provides polling driver implementation of pop_multishot returning None (no multishot support)
compio-driver/src/sys/iour/op.rs	Implements the three new multishot operation types with fallback to single-shot managed operations, and refactors code with take_buffer helper
compio-driver/src/sys/iour/mod.rs	Core multishot support including result queue management, completion handling with more flag detection, and fallback logic
compio-driver/src/sys/iocp/mod.rs	Provides IOCP driver stub for pop_multishot returning None
compio-driver/src/sys/fusion/op.rs	Adds macro invocations for the three multishot operations in fusion driver
compio-driver/src/sys/fusion/mod.rs	Delegates pop_multishot calls to underlying driver and exports take_buffer helper
compio-driver/src/op.rs	Exports new multishot operations and implements ResultTakeBuffer for BufResult<usize, Extra> to support buffer extraction
compio-driver/src/lib.rs	Adds public pop_multishot method to Proactor API
compio-driver/src/key.rs	Adds wake_by_ref method to FrozenKey for waking tasks without consuming the key

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[Berrysoft]

Oh, no. #716 only handles ReadMulti, but cannot handle SendMulti or AcceptMulti, as the opcode are the same for oneshot/multishot ops. There's no way to probe.

[George-Miao]

We can implement Ord for ErasedKey if you prefer BTreeMap.

[Berrysoft]

Either one is OK.

[George-Miao]

LGTM