code: protected Response post(StreamingOutput stream, String mediaType, Object... pathArgs) throws IOException {
          URL url = getApiUrl(pathArgs);
          return (invocation(url, null).post(Entity.entity(stream, mediaType)));
      }
docs: Perform an HTTP POST call with the specified StreamingOutput, MediaType, and path objects, returning
  a ClientResponse instance with the data returned from the endpoint.
  
  @param stream the StreamingOutput instance that contains the POST data
  @param mediaType the content-type of the POST data
  @param pathArgs variable list of arguments used to build the URI
  @return a ClientResponse instance with the data returned from the endpoint
  @throws IOException if an error occurs while constructing the URL