Function impl_pairs_and_index

pub fn impl_pairs_and_index<T, M>(methods: &mut M)
where
    T: UserData + Serialize,
    M: UserDataMethods<T>,

Provides implementations of __pairs and __index metamethods for a type that is Serialize and UserData. Neither implementation is considered to be ideal, as we must first serialize the value into a json Value which is then either iterated over, or indexed to produce the appropriate result for the metamethod.