create a QuicError type

protocol/quic_error.go

@@ -0,0 +1,21 @@
+package protocol
+
+// A QuicError is a QUIC error
+type QuicError struct {
+	ErrorCode    ErrorCode
+	ErrorMessage string
+}
+
+// NewQuicError creates a new Quic Error
+func NewQuicError(errorCode ErrorCode, errorMessage string) *QuicError {
+	return &QuicError{
+		ErrorCode:    errorCode,
+		ErrorMessage: errorMessage,
+	}
+}
+
+func (e *QuicError) Error() string {
+	return e.ErrorMessage
+}
+
+var _ error = &QuicError{}