Fix: grpc transport concurrent write

component/gun/gun.go

@@ -5,6 +5,7 @@ package gun
 
 import (
 	"bufio"
+	"bytes"
 	"crypto/tls"
 	"encoding/binary"
 	"errors"
@@ -30,6 +31,7 @@ var (
 		"content-type": []string{"application/grpc"},
 		"user-agent":   []string{"grpc-go/1.36.0"},
 	}
+	bufferPool = sync.Pool{New: func() interface{} { return &bytes.Buffer{} }}
 )
 
 type DialFn = func(network, addr string) (net.Conn, error)
@@ -119,13 +121,20 @@ func (g *Conn) Read(b []byte) (n int, err error) {
 }
 
 func (g *Conn) Write(b []byte) (n int, err error) {
-	protobufHeader := appendUleb128([]byte{0x0A}, uint64(len(b)))
+	protobufHeader := [binary.MaxVarintLen64 + 1]byte{0x0A}
+	varuintSize := binary.PutUvarint(protobufHeader[1:], uint64(len(b)))
 	grpcHeader := make([]byte, 5)
-	grpcPayloadLen := uint32(len(protobufHeader) + len(b))
+	grpcPayloadLen := uint32(varuintSize + 1 + len(b))
 	binary.BigEndian.PutUint32(grpcHeader[1:5], grpcPayloadLen)
 
-	buffers := net.Buffers{grpcHeader, protobufHeader, b}
-	_, err = buffers.WriteTo(g.writer)
+	buf := bufferPool.Get().(*bytes.Buffer)
+	defer bufferPool.Put(buf)
+	defer buf.Reset()
+	buf.Write(grpcHeader)
+	buf.Write(protobufHeader[:varuintSize+1])
+	buf.Write(b)
+
+	_, err = g.writer.Write(buf.Bytes())
 	if err == io.ErrClosedPipe && g.err != nil {
 		err = g.err
 	}