logging: add a Debug function to the Tracer

internal/mocks/logging/mockgen.go

@@ -14,6 +14,7 @@ type Tracer interface {
 	SentPacket(net.Addr, *logging.Header, logging.ByteCount, []logging.Frame)
 	SentVersionNegotiationPacket(_ net.Addr, dest, src logging.ArbitraryLenConnectionID, _ []logging.VersionNumber)
 	DroppedPacket(net.Addr, logging.PacketType, logging.ByteCount, logging.PacketDropReason)
+	Debug(name, msg string)
 }
 
 //go:generate sh -c "go run go.uber.org/mock/mockgen -typed -build_flags=\"-tags=gomock\" -package internal -destination internal/connection_tracer.go github.com/quic-go/quic-go/internal/mocks/logging ConnectionTracer"

internal/mocks/logging/tracer.go

@@ -25,5 +25,8 @@ func NewMockTracer(ctrl *gomock.Controller) (*logging.Tracer, *MockTracer) {
 		DroppedPacket: func(remote net.Addr, typ logging.PacketType, size logging.ByteCount, reason logging.PacketDropReason) {
 			t.DroppedPacket(remote, typ, size, reason)
 		},
+		Debug: func(name, msg string) {
+			t.Debug(name, msg)
+		},
 	}, t
 }

logging/multiplex_test.go

@@ -64,6 +64,12 @@ var _ = Describe("Tracing", func() {
 				tr2.EXPECT().DroppedPacket(remote, PacketTypeRetry, ByteCount(1024), PacketDropDuplicate)
 				tracer.DroppedPacket(remote, PacketTypeRetry, 1024, PacketDropDuplicate)
 			})
+
+			It("traces the Debug event", func() {
+				tr1.EXPECT().Debug("foo", "bar")
+				tr2.EXPECT().Debug("foo", "bar")
+				tracer.Debug("foo", "bar")
+			})
 		})
 	})
 

logging/tracer.go

@@ -7,6 +7,7 @@ type Tracer struct {
 	SentPacket                   func(net.Addr, *Header, ByteCount, []Frame)
 	SentVersionNegotiationPacket func(_ net.Addr, dest, src ArbitraryLenConnectionID, _ []VersionNumber)
 	DroppedPacket                func(net.Addr, PacketType, ByteCount, PacketDropReason)
+	Debug                        func(name, msg string)
 }
 
 // NewMultiplexedTracer creates a new tracer that multiplexes events to multiple tracers.
@@ -39,5 +40,12 @@ func NewMultiplexedTracer(tracers ...*Tracer) *Tracer {
 				}
 			}
 		},
+		Debug: func(name, msg string) {
+			for _, t := range tracers {
+				if t.Debug != nil {
+					t.Debug(name, msg)
+				}
+			}
+		},
 	}
 }