docs: public /*@Nullable*/String createCopyRef(String path)
          throws DbxException
      {
          DbxPathV1.checkArgNonRoot("path", path);
  
          String apiPath = "1/copy_ref/auto" + path;
  
          return doPost(host.getApi(), apiPath, null, null, new DbxRequestUtil.ResponseHandler</*@Nullable*/String>()
          {
              @Override
              public /*@Nullable*/String handle(HttpRequestor.Response response)
                  throws DbxException
              {
                  if (response.getStatusCode() == 404) return null;
                  if (response.getStatusCode() != 200) throw DbxRequestUtil.unexpectedStatus(response);
                  CopyRef copyRef = DbxRequestUtil.readJsonFromResponse(CopyRef.Reader, response);
                  return copyRef.id;
              }
          });
      }