code: int getFileCrc(String src) throws IOException {
      checkOpen();
      return getFileCrc(dataTransferVersion,
          src, namenode, namenodeProtocolProxy, socketFactory, socketTimeout);
    }
docs: Get the CRC32 Checksum of a file.
  @param src The file path
  @return The checksum
  @see DistributedFileSystem#getFileCrc(Path)