public org.apache.flink.table.descriptors.Elasticsearch host(String hostname, int port, String protocol) {
		final Host host =
			new Host(
				Preconditions.checkNotNull(hostname),
				port,
				Preconditions.checkNotNull(protocol));
		hosts.add(host);
		return this;
	}
Adds an Elasticsearch host to connect to. Required.

<p>Multiple hosts can be declared by calling this method multiple times.

@param hostname connection hostname
@param port connection port
@param protocol connection protocol; e.g. "http"
elasticsearch5-xh/elasticsearch5-xh-sink/src/main/java/org/apache/flink/table/descriptors/Elasticsearch.java