Use channel to implement a simple way to wait

client.go

@@ -6,7 +6,6 @@ import (
 	"io"
 	"os"
 	"path"
-	"sync"
 	"sync/atomic"
 	"syscall"
 	"time"
@@ -123,7 +122,7 @@ func NewClientPipe(rd io.Reader, wr io.WriteCloser, opts ...ClientOption) (*Clie
 				WriteCloser: wr,
 			},
 			inflight: make(map[uint32]chan<- result),
-			errCond:  sync.NewCond(new(sync.Mutex)),
+			closed:   make(chan struct{}),
 		},
 		maxPacket:             1 << 15,
 		maxConcurrentRequests: 64,

conn.go

@@ -37,19 +37,15 @@ type clientConn struct {
 	sync.Mutex                          // protects inflight
 	inflight   map[uint32]chan<- result // outstanding requests
 
-	errCond *sync.Cond
-	err     error
+	closed chan struct{}
+	err    error
 }
 
 // Wait blocks until the conn has shut down, and return the error
 // causing the shutdown. It can be called concurrently from multiple
 // goroutines.
 func (c *clientConn) Wait() error {
-	c.errCond.L.Lock()
-	defer c.errCond.L.Unlock()
-	for c.err == nil {
-		c.errCond.Wait()
-	}
+	<-c.closed
 	return c.err
 }
 
@@ -64,10 +60,6 @@ func (c *clientConn) loop() {
 	err := c.recv()
 	if err != nil {
 		c.broadcastErr(err)
-		c.errCond.L.Lock()
-		c.err = err
-		c.errCond.Broadcast()
-		c.errCond.L.Unlock()
 	}
 }
 
@@ -141,6 +133,8 @@ func (c *clientConn) broadcastErr(err error) {
 	for _, ch := range listeners {
 		ch <- result{err: err}
 	}
+	c.err = err
+	close(c.closed)
 }
 
 type serverConn struct {