code: public void log(String message, final Callback callback) {
          if (message == null) return;
  
          loggly.log(token,
                  tags,
                  message,
                  new retrofit2.Callback<LogglyResponse>() {
                      @Override
                      public void onResponse(Call<LogglyResponse> call, Response<LogglyResponse> response) {
                          callback.success();
                      }
  
                      @Override
                      public void onFailure(Call<LogglyResponse> call, Throwable throwable) {
                          callback.failure(throwable.getMessage());
                      }
                  });
      }
docs: Posts a log message asynchronously to Loggly
  @param message message to be logged
  @param callback callback to be invoked on completion of the post