code: 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);
      }
docs: Initiates a multipart upload and returns an InitiateMultipartUploadResponse
  which contains an upload ID. This upload ID associates all the parts in
  the specific upload and is used in each of your subsequent uploadPart requests.
  You also include this upload ID in the final request to either complete, or abort the multipart
  upload request.
  
  @param request The InitiateMultipartUploadRequest object that specifies all the parameters of this operation.
  @return An InitiateMultipartUploadResponse from Bos.