@Override
  public String toString() {
    return "DataNode[" + getHostname() + ":" + getPort() + "]";
  }
Returns the {@link Port} of this node to connect to. A {@link Port} will be automatically selected based on if
there is a need of establishing an SSL connection.

@return {@link Port} to which the caller can connect to.
@throws IllegalStateException Thrown if an SSL connection is needed but no SSL port exists.
ambry-clustermap/src/main/java/com/github/ambry/clustermap/DataNode.java