public void writeTo(Output output, int number, boolean repeated,
            Enum<?> e) throws IOException
    {
        if (0 == (IdStrategy.ENUMS_BY_NAME & strategy.flags))
            output.writeEnum(number, getTag(e), repeated);
        else
            output.writeString(number, getAlias(e), repeated);
    }
Writes the {@link Enum} to the output.
protostuff-runtime/src/main/java/io/protostuff/runtime/EnumIO.java