Available on crate features registry and std only.
Expand description
Uniquely identifies an individual Filter instance in the context of
a collector.
When adding a FilteredSubscribe to a collector, the collector
generates a FilterId for that Filtered subscriber. The Filtered subscriber
will then use the generated ID to query whether a particular span was
previously enabled by that subscriber’s Filter.
Note: Currently, the Registry type provided by this crate is the
onlyCollect implementation capable of participating in per-subscriber
filtering. Therefore, the FilterId type cannot currently be constructed by
code outside of tracing-subscriber. In the future, new APIs will be added to tracing-subscriber to
allow non-Registry collectors to also participate in per-subscriber
filtering. When those APIs are added, subscribers will be responsible
for generating and assigning FilterIds.