async-io-model

Manage non-blocking I/O operations without Rust async/await by using cooperative yielding and explicit state machines. This approach enforces IOResult and IOCompletions primitives to make IO progress deterministic and reduce re-entrancy bugs.

Prevent re-entrancy bugs during core storage reads and writes by adopting state-machine driven operation patterns. Mutate state only after IO completion and use return_if_io! and io_yield_one! macros to manage safe yields and resumes.

Aggregate multiple I/O operations into a single completion by using CompletionGroup. This primitive provides built-in cancellation support, allowing you to manage grouped I/O-bound tasks efficiently within the core I/O layers.

Implement a basic yield and resume state machine by studying core types and completion structures, then writing a tiny operation that yields once using io_yield_one! and resumes to completion. Adapt this pattern to read workflows in btree or pager modules.

Use cooperative yielding instead of standard Rust async for I/O-bound tasks when deterministic IO progress and explicit state management are required. This approach avoids async/await complexity, directly addressing re-entrancy hazards across core storage and background maintenance operations.