code: @Override
      protected Request.Builder setBody(Request.Builder builder) {
          if (body != null) {
              MultipartBody.Builder bodyBuilder = createMultipartBody();
              RequestBody requestBody = bodyBuilder.build();
              if ("PUT".equalsIgnoreCase(method))
                  builder.put(requestBody);
              else if ("POST".equalsIgnoreCase(method))
                  builder.post(requestBody);
          }
          return builder;
      }
docs: set request body