TraceHandler wraps a HTTPHandler and import trace information from header.

TraceInfoFromHeader will create a TraceInfo object given a http.Header or anything that matches the HeaderGetter interface.

TraceRequest will perform an HTTP request, creating a new Span for the HTTP request and sending the Span in the HTTP request headers.

Wrap wraps original writer + provides func to retrieve statusCode, implements http.Flusher if original writer also did it.

TraceInfo is a structure representing an incoming RPC request.

Client is an interface that matches a http.Client.

HeaderGetter is an interface that http.Header matches for RequestFromHeader.

HeaderSetter is an interface that http.Header matches for TraceInfo.SetHeader.