in qf.go [463:470]
func (qf *Filter) Lookup(key []byte) (bool, uint64) {
dq, dr := hash(qf.hashfn, key, qf.rBits, qf.rMask)
var storageFn readFn
if qf.storage != nil {
storageFn = qf.storage.Get
}
return lookupByHash(dq, dr, qf.size, qf.filter.Get, storageFn)
}