Function unknown_instrument 

pub async fn unknown_instrument<M: OrderBookSource + ?Sized>(
    md: &M,
    unknown: &InstrumentId,
)

A read of an instrument the broker does not know is Rejected(not_found), the same at every broker.

Not Transport (that would invite a retry), not Ok, not a differently spelled code.

Panics

With [conformance:unknown_instrument] <reason>.