// Successful receive on rdRx is always followed by send on rdTx.
	rdRx <-chan []byte
	rdTx chan<- int

	// Used by local Write to interact with remote Read.
	// Successful send on wrTx is always followed by receive on wrRx.
	wrTx chan<- []byte
	wrRx <-chan int

	once       sync.Once // Protects closing localDone
	localDone  chan struct{}
	remoteDone <-chan struct{}

	readDeadline  pipeDeadline
	writeDeadline pipeDeadline