TUN-4597: Add a QUIC server skeleton

- Added a QUIC server to accept streams
- Unit test for this server also tests ALPN
- Temporary echo capability for HTTP ConnectionType

vendor/github.com/lucas-clemente/quic-go/internal/protocol/stream.go

@@ -0,0 +1,76 @@
+package protocol
+
+// StreamType encodes if this is a unidirectional or bidirectional stream
+type StreamType uint8
+
+const (
+	// StreamTypeUni is a unidirectional stream
+	StreamTypeUni StreamType = iota
+	// StreamTypeBidi is a bidirectional stream
+	StreamTypeBidi
+)
+
+// InvalidPacketNumber is a stream ID that is invalid.
+// The first valid stream ID in QUIC is 0.
+const InvalidStreamID StreamID = -1
+
+// StreamNum is the stream number
+type StreamNum int64
+
+const (
+	// InvalidStreamNum is an invalid stream number.
+	InvalidStreamNum = -1
+	// MaxStreamCount is the maximum stream count value that can be sent in MAX_STREAMS frames
+	// and as the stream count in the transport parameters
+	MaxStreamCount StreamNum = 1 << 60
+)
+
+// StreamID calculates the stream ID.
+func (s StreamNum) StreamID(stype StreamType, pers Perspective) StreamID {
+	if s == 0 {
+		return InvalidStreamID
+	}
+	var first StreamID
+	switch stype {
+	case StreamTypeBidi:
+		switch pers {
+		case PerspectiveClient:
+			first = 0
+		case PerspectiveServer:
+			first = 1
+		}
+	case StreamTypeUni:
+		switch pers {
+		case PerspectiveClient:
+			first = 2
+		case PerspectiveServer:
+			first = 3
+		}
+	}
+	return first + 4*StreamID(s-1)
+}
+
+// A StreamID in QUIC
+type StreamID int64
+
+// InitiatedBy says if the stream was initiated by the client or by the server
+func (s StreamID) InitiatedBy() Perspective {
+	if s%2 == 0 {
+		return PerspectiveClient
+	}
+	return PerspectiveServer
+}
+
+// Type says if this is a unidirectional or bidirectional stream
+func (s StreamID) Type() StreamType {
+	if s%4 >= 2 {
+		return StreamTypeUni
+	}
+	return StreamTypeBidi
+}
+
+// StreamNum returns how many streams in total are below this
+// Example: for stream 9 it returns 3 (i.e. streams 1, 5 and 9)
+func (s StreamID) StreamNum() StreamNum {
+	return StreamNum(s/4) + 1
+}