code: public Mono<HttpResponse> send(HttpPipelineCallContext context) {
          // Return deferred to mono for complete lazy behaviour.
          //
          return Mono.defer(() -> {
              HttpPipelineNextPolicy next = new HttpPipelineNextPolicy(this, context);
              return next.process();
          });
      }
docs: Sends the context (containing request) through pipeline.
  
  @param context the request context
  @return a publisher upon subscription flows the context through policies, sends the request and emits response upon completion