code: public static FastByteArrayOutputStream read(ReadableByteChannel channel) throws IORuntimeException {
  		final FastByteArrayOutputStream out = new FastByteArrayOutputStream();
  		copy(channel, Channels.newChannel(out));
  		return out;
  	}
docs: 从流中读取内容，读到输出流中
  
  @param channel 可读通道，读取完毕后并不关闭通道
  @return 输出流
  @throws IORuntimeException IO异常