Term	Meaning
Active message	A message that names a handler on the remote instance. The handler runs when the message arrives.
Admission	The step where a transport puts an inbound request on the queue with TransportAdapter::admit_message. Admission takes the in-flight guard.
Admission gate	The queue for one target (and lane) that holds sends while the bounded send channel is full
Anchor	The consumer end of a stream. It has a u128 handle that a producer uses to attach.
Attach	The _anchor_attach round trip that connects a producer to an anchor
Batch	One messenger frame that carries records from many streams to one peer
Coalescing writer	The TCP, UDS, and QUIC writer task. It writes small queued frames together, and a large frame as two writes.
Credit	The number of records that a sender can send on a slot before the receiver grants more
Drain	The second phase of graceful shutdown. Velo waits until no admitted request is in flight.
Frame transport	A transport for stream frames when the mux is not used (TCP or gRPC)
Gate	The first phase of graceful shutdown. New inbound requests are refused.
InstanceId	The identity of one Velo instance
Mux	Batched streaming. Records from many streams share messenger frames to the same peer.
Ordered lane	For an ordered handler, the queue and task for one sender (or for all senders with ordered_global). Not the same as a transport lane.
Pre-bind	prebind_anchor. The consumer makes a ticket, so the producer can open the stream with no attach round trip.
Primary transport	The compatible transport with the highest priority for a peer
Rendezvous	Transfer of a large payload by handle. The owner stages the bytes, and the peer pulls them.
RDMA GET	A one-sided read by the NIC of the peer from registered memory on the owner
Slot	The identity of one stream inside the mux, with its own order and credit
Teardown	The third phase of graceful shutdown. Velo cancels tokens and stops the transports.
Close	The fourth phase of graceful shutdown. Velo waits for Transport::closed() on each transport, so that what it wrote reaches the peer.
Ticket	A StreamOpenTicket. It carries the terms of a pre-bound stream.
Transport lane	One ordered channel from a transport to a peer. Order holds within a lane only. QUIC and TCP can keep several lanes to a peer, each on its own connection. Not the same as an ordered lane.
TransportKey	The name of a transport in a WorkerAddress, for example tcp
WorkerAddress	A MessagePack map from TransportKey to endpoint bytes
WorkerId	The identity of a worker. A StreamAnchorHandle encodes it.