if (throwable != null) {
if (!(throwable instanceof ThrowableProxy)) {
super.format(event, toAppendTo);
return;
}
ThrowableProxy t = (ThrowableProxy) throwable;
String trace = t.getRootCauseStackTrace();
int len = toAppendTo.length();
if (len > 0 && !Character.isWhitespace(toAppendTo.charAt(len - 1))) {
toAppendTo.append(" ");
}
if (lines > 0) {