Registers, or with no function removes, a protocol family's narrowing of
the subjects its own applications' streams may carry. A scope can only take
events away.
Parameters
Optionalfamily: any
the family's name
Optionalfn: any
(record, subject) answering true, false, or undefined for
a stream that is not the family's
Registers, or with no function removes, a protocol family's narrowing of the subjects its own applications' streams may carry. A scope can only take events away.