public static void injectEdge(EnvironmentEdge edge) {
    if (edge == null) {
      reset();
    } else {
      delegate = edge;
    }
  }
Injects the given edge such that it becomes the managed entity. If null is passed to this
method, the default type is assigned to the delegate.
@param edge the new edge.
hbase-common/src/main/java/org/apache/hadoop/hbase/util/EnvironmentEdgeManager.java