Function protobuf::reflect::accessor::make_option_accessor

pub fn make_option_accessor<M, V>(name: &'static str,
                                  get_field: fn<'a>(_: &'a M) -> &'a Option<V::Value>,
                                  mut_field: fn<'a>(_: &'a mut M) -> &'a mut Option<V::Value>)
                                  -> Box<FieldAccessor + 'static> where M: Message + 'static, V: ProtobufType + 'static