pub struct FilterId(/* private fields */);
Expand description
Uniquely identifies an individual Filter
instance in the context of
a Subscriber
.
When adding a Filtered
Layer
to a Subscriber
, the Subscriber
generates a FilterId
for that Filtered
layer. The Filtered
layer
will then use the generated ID to query whether a particular span was
previously enabled by that layer’s Filter
.
Note: Currently, the Registry
type provided by this crate is the
only Subscriber
implementation capable of participating in per-layer
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 Subscriber
s to also participate in per-layer
filtering. When those APIs are added, subscribers will be responsible
for generating and assigning FilterId
s.