Function set_report_sink 

pub fn set_report_sink(sink: fn(&str)) -> bool

Route every scan diagnostic in this crate — report_oversized_ids and super::malformed_records::report_malformed_records alike — to sink instead of stderr.

Returns true when this call installed the sink, false when one was already installed (the first wins). Callers on wasm32 MUST install one: the default sink is eprintln!, which that target discards.