Singleton instance.
Prints the current stack trace if available to a PrintWriter. The format is undefined and is primarily useful for debugging issues with {@link PooledObject} usage in user code.
Takes a snapshot of the current call stack. Subsequent calls to {@link #printStackTrace(PrintWriter)} will print out that stack trace until it is {@linkplain #clear() cleared}.
Clears the current stack trace snapshot. Subsequent calls to {@link #printStackTrace(PrintWriter)} will be no-ops until another call to {@link #fillInStackTrace()}.
CallStack strategy using no-op implementations of all functionality. Can be used by default when abandoned object logging is disabled.