Function rustfst::algorithms::fst_convert_from_ref

pub fn fst_convert_from_ref<W, F1, F2>(ifst: &F1) -> F2 where
    W: Semiring,
    F1: Fst<W>,
    F2: MutableFst<W> + AllocableFst<W>, 

Generic method to convert an Fst into any other types implementing the MutableFst trait.