EventSource
This article applies to: ✔️ .NET Core 3.1 and later versions ✔️ .NET Framework 4.5 and later versions
System.Diagnostics.Tracing.EventSource is a fast structured logging solution built into the .NET runtime. On .NET Framework EventSource can send events to Event Tracing for Windows (ETW) and System.Diagnostics.Tracing.EventListener. On .NET Core EventSource additionally supports EventPipe, a cross-platform tracing option. Most often developers use EventSource logs for performance analysis, but EventSource can be used for any diagnostic tasks where logs are useful. The .NET runtime is already instrumented with built-in events and you can log your own custom events.
Note
Many technologies that integrate with EventSource use the terms 'Tracing' and 'Traces' instead of 'Logging' and 'Logs'. The meaning is the same here.