Function classify 

pub fn classify(e: &SessionError) -> Disposition

Classifies a session-establishment failure as transient (retry) or permanent (fail fast).

Inspects the inner io::ErrorKind and OBEX/server opcodes rather than the top-level variant, so “device asleep / out of range” (transient) is distinguished from “wrong channel / pairing rejected” (permanent). Anything not explicitly recognised defaults to Disposition::Transient: the retry budget bounds the cost of a wrong guess, whereas a wrong “permanent” verdict abandons a recoverable link.