Function protobuf::reflect::accessor::make_singular_field_accessor

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