Function summarize_function_via 

pub fn summarize_function_via<F>(
    dispatch: &F,
    fn_ast_in: &[u32],
    callgraph_in: &[u32],
    cached_summary_in: &[u32],
    bit_count: u32,
) -> Result<Vec<u32>, String>
where
    F: Fn(&Program, &[Vec<u8>], Option<[u32; 3]>) -> Result<Vec<Vec<u8>>, String>,