use GoJay to marshal JSON

GoJay doesn't use reflection to marshal JSON. This allows dramatically
faster encoding, as well as saving a large number of allocations.

qlog/types.go

@@ -0,0 +1,37 @@
+package qlog
+
+import (
+	"fmt"
+	"strconv"
+
+	"github.com/lucas-clemente/quic-go/internal/protocol"
+)
+
+func toString(i int64) string {
+	return strconv.FormatInt(i, 10)
+}
+
+type versionNumber protocol.VersionNumber
+
+func (v versionNumber) String() string {
+	return fmt.Sprintf("%x", uint32(v))
+}
+
+type streamType protocol.StreamType
+
+func (s streamType) String() string {
+	switch protocol.StreamType(s) {
+	case protocol.StreamTypeUni:
+		return "unidirectional"
+	case protocol.StreamTypeBidi:
+		return "bidirectional"
+	default:
+		panic("unknown stream type")
+	}
+}
+
+type connectionID protocol.ConnectionID
+
+func (c connectionID) String() string {
+	return fmt.Sprintf("%x", []byte(c))
+}