public CompletableFuture<AsyncConnection> createAsyncConnection() {
    if (miniCluster == null) {
      throw new IllegalStateException("test cluster not initialized");
    }
    return ConnectionFactory.createAsyncConnection(miniCluster.getConf());
  }
Create a {@link AsyncConnection} to the managed {@link SingleProcessHBaseCluster}. It's up to
the caller to {@link AsyncConnection#close() close()} the connection when finished.
hbase-server/src/test/java/org/apache/hadoop/hbase/MiniClusterRule.java