docs: public InitiateMultipartUploadResponse initiateMultipartUpload(InitiateMultipartUploadRequest request) {
          checkNotNull(request, "request should not be null.");
  
          InternalRequest internalRequest = this.createRequest(request, HttpMethodName.POST);
          internalRequest.addParameter("uploads", null);
          if (request.getStorageClass() != null) {
              internalRequest.addHeader(Headers.BCE_STORAGE_CLASS, request.getStorageClass());
          }
          this.setZeroContentLength(internalRequest);
  
          if (request.getObjectMetadata() != null) {
              populateRequestMetadata(internalRequest, request.getObjectMetadata());
          }
  
          return this.invokeHttpClient(internalRequest, InitiateMultipartUploadResponse.class);
      }