go/src/net/textproto/pipeline.go

type Pipeline …

// Next returns the next id for a request/response pair.
func (p *Pipeline) Next() uint { … }

// StartRequest blocks until it is time to send (or, if this is a server, receive)
// the request with the given id.
func (p *Pipeline) StartRequest(id uint) { … }

// EndRequest notifies p that the request with the given id has been sent
// (or, if this is a server, received).
func (p *Pipeline) EndRequest(id uint) { … }

// StartResponse blocks until it is time to receive (or, if this is a server, send)
// the request with the given id.
func (p *Pipeline) StartResponse(id uint) { … }

// EndResponse notifies p that the response with the given id has been received
// (or, if this is a server, sent).
func (p *Pipeline) EndResponse(id uint) { … }

type sequencer …

// Start waits until it is time for the event numbered id to begin.
// That is, except for the first event, it waits until End(id-1) has
// been called.
func (s *sequencer) Start(id uint) { … }

// End notifies the sequencer that the event numbered id has completed,
// allowing it to schedule the event numbered id+1.  It is a run-time error
// to call End with an id that is not the number of the active event.
func (s *sequencer) End(id uint) { … }