public synchronized static RootMetricContext get(List<Tag<?>> tags) {
    if (INSTANCE == null) {
      initialize(tags);
    }
    return INSTANCE;
  }
public synchronized static RootMetricContext get ( List < Tag < ? > > tags ) { if ( INSTANCE == null ) { initialize ( tags ) ; } return INSTANCE ; }
Get the singleton {@link RootMetricContext}, adding the specified tags if and only if this is the first call.
@return singleton instance of {@link RootMetricContext}.