default void preSwitchExceedThrottleQuota(final ObserverContext<MasterCoprocessorEnvironment> ctx,
    final boolean enable) throws IOException {
  }
Called before switching exceed throttle quota state.
@param ctx    the coprocessor instance's environment
@param enable the exceed throttle quota value
hbase-server/src/main/java/org/apache/hadoop/hbase/coprocessor/MasterObserver.java