code: public ServiceFuture<PersistedFace> addFaceFromUrlAsync(String faceListId, String url, AddFaceFromUrlOptionalParameter addFaceFromUrlOptionalParameter, final ServiceCallback<PersistedFace> serviceCallback) {
          return ServiceFuture.fromResponse(addFaceFromUrlWithServiceResponseAsync(faceListId, url, addFaceFromUrlOptionalParameter), serviceCallback);
      }
docs: Add a face to a face list. The input face is specified as an image with a targetFace rectangle. It returns a persistedFaceId representing the added face, and persistedFaceId will not expire.
  
  @param faceListId Id referencing a particular face list.
  @param url Publicly reachable URL of an image
  @param addFaceFromUrlOptionalParameter the object representing the optional parameters to be set before calling this API
  @param serviceCallback the async ServiceCallback to handle successful and failed responses.
  @throws IllegalArgumentException thrown if parameters fail the validation
  @return the {@link ServiceFuture} object