code: static void writeNullableString(final String value, final DataOutput out)
  		throws IOException
  	{
  		writeNullable(value, IO::writeString, out);
  	}
docs: Write the given string, possible {@code null}, {@code value} to the given
  data output.
  
  @param value the string value to write
  @param out the data output
  @throws NullPointerException if the given data output is {@code null}
  @throws IOException if an I/O error occurs