Binary messenger and transport

IBinaryMessenger sends named binary requests and registers asynchronous incoming handlers. BinaryMessenger owns correlation IDs, pending state, cancellation, timeout timers, handler ownership, and reply completion. IChannelTransport carries request frames and response statuses; production NativeChannelTransport implements it using the generic Kotlin or Swift bridge.

InMemoryTransport.CreatePair() provides portable bidirectional endpoints for tests and nonplatform experiments. Construct a messenger and ChannelService for each endpoint. The portable core solution never requires MAUI workloads.

The messenger queues handler entry in FIFO order. An asynchronous handler releases the dispatcher at its first suspension, allowing reentrant calls and out-of-order completion. Pending entries are removed on success, error, cancellation, timeout, and disposal. PendingRequestCount supports diagnostics. Service disposal owns its messenger, which owns its transport. Use DisposeAsync when teardown must be complete before continuing. Synchronous DI disposal initiates asynchronous native draining.