code: public Response post(String endpoint, Request params) {
          return call(Method.POST, endpoint, params, null);
      }
docs: Performs a post http call and writes the call and response information to
  the output file
  
  @param endpoint - the endpoint of the service under test
  @param params   - the parameters to be passed to the endpoint for the service
  call
  @return Response: the response provided from the http call