Simple console appender that counts the number of log lines it has written.
Allows the dynamic setting of log levels on a per-thread basis. Imagine that a user request comes into your production threaded server. You can't afford to turn logging up to trace for the sake of debugging this one users problem, but you also can't afford to find the problem and fix it. So now you just set the override log level to TRACE for the thread the user is on, and you get full trace output for only that user.
Testing harness for the DiagnosticContext functionality.