Function protobuf::reflect::accessor::make_has_get_mut_clear_accessor

pub fn make_has_get_mut_clear_accessor<M, V>(_name: &'static str,
                                             _has_value: fn<'a>(_: &'a M) -> bool,
                                             _get_value: fn<'a>(_: &'a M) -> &'a V::Value,
                                             _mut_value: fn<'a>(_: &'a M) -> &'a mut V::Value,
                                             _clr_value: fn<'a>(_: &'a M))
                                             -> Box<FieldAccessor + 'static> where M: Message + 'static, V: ProtobufType + 'static