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<dyn FieldAccessor + 'static> where
    M: Message + 'static,
    V: ProtobufType + 'static,