even package:base-prelude

Immediately flush the event log, if enabled.
The traceEvent function behaves like trace with the difference that the message is emitted to the eventlog, if eventlog profiling is available and enabled at runtime. It is suitable for use in pure code. In an IO context use traceEventIO instead. Note that when using GHC's SMP runtime, it is possible (but rare) to get duplicate events emitted if two CPUs simultaneously evaluate the same thunk that uses traceEvent.
The traceEventIO function emits a message to the eventlog, if eventlog profiling is available and enabled at runtime. Compared to traceEvent, traceEventIO sequences the event with respect to other IO actions.