GCEventsHandling.cs

var source = userSession.Source;
source.NeedLoadedDotNetRuntimes();
source.AddCallbackOnProcessStart((TraceProcess proc) =>
{
    proc.AddCallbackOnDotNetRuntimeLoad((TraceLoadedDotNetRuntime runtime) =>
    {
        runtime.GCStart += (TraceProcess p, TraceGC gc) =>
        {
            // a GC is starting
        };
        runtime.GCEnd += (TraceProcess p, TraceGC gc) =>
        {
            // a GC ends
        };
    });
});