func (m *traceMiddleware) Handle(rw protocol.ResponseWriter, req *protocol.Request) {
m.wrapped.Handle(rw, req)
traceId := req.Header.Get(TraceHeader)
if traceId == "" {
traceId = uuid.New()
}
rw.Header().Set(TraceHeader, traceId)
// TODO: Logging with trace id.
}
