Module serial 

Low-level serial I/O traits, device discovery, handshake, frame reader, and writer task.

This module encapsulates all direct interaction with the serial byte stream below the Go-Back-N ResendSP state machines:

• RX (SerialReader): Rather than spawning a separate reader_task, incoming bytes are parsed by SerialReader, which is borrowed directly by the receiver task (reader.next_frame().await). This allows the caller to recover any unconsumed trailing bytes via SerialReader::take_unconsumed when a session ends or renegotiates.
• TX (writer_task): Because multiple producers emit frames concurrently (outgoing data/close frames, duplicate handshake replies, and priority cumulative ACKs via AckTracker), outgoing serial writes are handled by a dedicated writer_task that prioritizes ACKs and coalesces 4 KiB frame batches.

Structs

SerialReader

Buffered UART protocol frame reader wrapping a SerialRead implementation.

Traits

SerialRead

Asynchronous byte reader abstraction over a target serial device.

SerialWrite

Asynchronous byte writer abstraction over a target serial device.

Functions

open_serial_device

Discovers a serial device under /dev/class/serial and configures it for 8N1 at baud_rate.

run_target_handshake

Runs the target-side framing protocol handshake over device.

run_target_handshake_with_initial_data

Runs the target-side framing protocol handshake seeded with initial_data.

writer_task

Runs the serial frame writer loop, prioritizing pending ACKs from ack_tracker ahead of coalesced outgoing data frames from data_rx.