Carry DATA and FILE_DATA only through the duplex SPSC streams. Keep LGMP
queues for control and status. Remove grants, commits, ACKs, and
queue-payload transport negotiation.
Poll adaptively while ownership or release is active. Preserve FIFO
release and graceful draining. Quarantine payloads crossed by a newer
OFFER or CLEAR, and retire data-plane state on detach.
Attach the advertised clipboard lanes before claiming ownership, prefer
the stream transport, and activate only the acknowledged client and
epoch binding.
Move representation and file payloads through fixed-slot reservations
while status and lifecycle control remain on the LGMP queue. Retain a
legacy v4 fallback for other hosts.
Hold each host-to-client reservation until the consumer accepts its
record, return credits in order, and drain queued traffic in bounded
bursts before sleeping.
Mark the last non-empty FILE_DATA payload with BEGIN and END when the
producer knows it is terminal. Complete producer bookkeeping in the
following fileDataEnd call without consuming another LGMP grant. Keep
the standalone terminal record for empty and legacy unknown streams.
Drain up to 64 queued clipboard records per worker pass instead of
sleeping after every message. Poll at 1 ms while transfers, blocked
writes, held input, or pending output are active, and retain the 10 ms
interval while idle.
This removes a serialized grant round trip from every non-empty file
response and reduces scheduling delay while a large transfer is active.
Keep the 1 MiB payload size because the bottleneck was stop-and-wait
latency, not the chunk capacity.
Exercise a full 1 MiB response in a single BEGIN|END grant and retain
coverage for empty unknown-size responses.
