implement net.Error interface for stream deadline expiration errors

interface.go

@@ -10,7 +10,13 @@ import (
 
 // Stream is the interface implemented by QUIC streams
 type Stream interface {
+	// Read reads data from the stream.
+	// Read can be made to time out and return a net.Error with Timeout() == true
+	// after a fixed time limit; see SetDeadline and SetReadDeadline.
 	io.Reader
+	// Write writes data to the stream.
+	// Write can be made to time out and return a net.Error with Timeout() == true
+	// after a fixed time limit; see SetDeadline and SetWriteDeadline.
 	io.Writer
 	io.Closer
 	StreamID() protocol.StreamID

stream.go

@@ -1,9 +1,9 @@
 package quic
 
 import (
-	"errors"
 	"fmt"
 	"io"
+	"net"
 	"sync"
 	"time"
 
@@ -55,7 +55,13 @@ type stream struct {
 	flowControlManager flowcontrol.FlowControlManager
 }
 
-var errDeadline = errors.New("deadline exceeded")
+type deadlineError struct{}
+
+func (deadlineError) Error() string   { return "deadline exceeded" }
+func (deadlineError) Temporary() bool { return true }
+func (deadlineError) Timeout() bool   { return true }
+
+var errDeadline net.Error = &deadlineError{}
 
 // newStream creates a new Stream
 func newStream(StreamID protocol.StreamID,

stream_test.go

@@ -255,6 +255,11 @@ var _ = Describe("Stream", func() {
 		})
 
 		Context("deadlines", func() {
+			It("the deadline error has the right net.Error properties", func() {
+				Expect(errDeadline.Temporary()).To(BeTrue())
+				Expect(errDeadline.Timeout()).To(BeTrue())
+			})
+
 			It("returns an error when Read is called after the deadline", func() {
 				mockFcm.EXPECT().UpdateHighestReceived(streamID, protocol.ByteCount(6)).AnyTimes()
 				f := &frames.StreamFrame{Data: []byte("foobar")}