Automated onError() message generation

File.java

public static Action1<Throwable> crashOnError() {
    final Throwable checkpoint = new Throwable();
    return throwable -> {
        StackTraceElement[] stackTrace = checkpoint.getStackTrace();
        StackTraceElement element = stackTrace[1]; // First element after `crashOnError()`
        String msg = String.format("onError() crash from subscribe() in %s.%s(%s:%s)",
            element.getClassName(),
            element.getMethodName(),
            element.getFileName(),
            element.getLineNumber());

        throw new OnErrorNotImplementedException(msg, throwable);
    };
}