code: public void writeBinaryString(byte[] data, int offset, int len)
  			throws IOException {
  		if (data == null)
  			writeInt(0);
  		else {
  			writeInt(len);
  			write(data, offset, len);
  		}
  	}
docs: Write a binary string to the array.
  
  @param data
  @param offset
  @param len
  @throws IOException