
  -spec atom_to_binary(Atom, Encoding) -> binary()
                          when
                              Atom :: atom(),
                              Encoding :: latin1 | unicode | utf8.

  Returns a binary corresponding to the text representation of Atom.
  If Encoding is latin1, one byte exists for each character in
  the text representation. If Encoding is utf8 or unicode, the
  characters are encoded using UTF-8 where characters may require
  multiple bytes.

  Note:
    As from Erlang/OTP 20, atoms can contain any Unicode character
    and atom_to_binary(Atom, latin1) may fail if the text
    representation for Atom contains a Unicode character > 255.

  Example:

    > atom_to_binary('Erlang', latin1).
    <<"Erlang">>
