Interface module for the Event Trace (ET) application
Reports an event, such as a message.
These functions are intended to be invoked at strategic places in user applications in order to enable simplified tracing. The functions are extremely light weight as they do nothing besides returning an atom. These functions are designed for being traced. The global tracing mechanism in et_collector defaults to set its trace pattern to these functions.
The label is intended to provide a brief summary of the event. A simple tag would do.
The contents can be any term but in order to simplify post processing of the traced events, a plain list of {Key, Value} tuples is preferred.
Some events, such as messages, are directed from some actor to another. Other events (termed actions) may be undirected and only have one actor.