public boolean isInitialized() {
    synchronized (SampleCollector.class) {
      synchronized (sampleHandlers) {
        return instance == this;
      }
    }
  }
Initializes this collector by creating a {@link StatArchiveHandler} and registering it as a
handler.

@param config defines the configuration for the StatArchiveHandler
@param nanosTimeStamp the nanos time stamp to initialize stat archiver with
@param rollingFileHandler provides file rolling behavior
geode-core/src/main/java/org/apache/geode/internal/statistics/SampleCollector.java