Package spanlog provides span and event logger interfaces that are used by the build coordinator infrastructure.
SpanLogger is something that has the CreateSpan method, which creates a event spanning some duration which will eventually be logged and visualized.
Span is a handle that can eventually be closed. Typical usage:
sp := sl.CreateSpan("slow_operation") result, err := doSlowOperation() sp.Done(err) // do something with result, err