TimeInstrument getLastTimeInstrument() {
        if (childTimeInstrumentList.size() > 0) {
            return childTimeInstrumentList.get(childTimeInstrumentList.size() - 1);
        } else {
            return null;
        }
    }
Starts a child stop watch and stops any previously started time
instruments.
slf4j-ext/src/main/java/org/slf4j/profiler/Profiler.java