code: protected void writeHeader() throws IOException {
  		this.tmpOutput.write(HEADER_KEY.getBytes());
  		this.tmpOutput.write(new byte[]{MAJOR_SPEC_NUMBER, MINOR_SPEC_NUMBER});
  		this.tmpOutput.write(new byte[] {0, 0, 0, 0});
  	}
docs: Write the header of the file.
  
  @throws IOException in case of error.