@Override
  public synchronized void write(int b) throws IOException {
    mUfsOutStream.write(b);
    mBytesWritten++;
  }
@Test
  public void writeOffset() throws IOException, AlluxioException {
    int bytesToWrite = CHUNK_SIZE * 5 + CHUNK_SIZE / 2;
    int offset = CHUNK_SIZE / 3;
    AlluxioURI ufsPath = getUfsPath();
    try (FileOutStream outStream = mFileSystem.createFile(ufsPath)) {
      byte[] array = BufferUtils.getIncreasingByteArray(bytesToWrite + offset);
      outStream.write(array, offset, bytesToWrite);
    }
    verifyIncreasingBytesWritten(ufsPath, offset, bytesToWrite);
  }