in flink-connector-opensearch/src/main/java/org/apache/flink/connector/opensearch/sink/OpensearchSinkBuilder.java [340:351]
private NetworkClientConfig buildNetworkClientConfig() {
checkArgument(!hosts.isEmpty(), "Hosts cannot be empty.");
return new NetworkClientConfig(
username,
password,
connectionPathPrefix,
connectionRequestTimeout,
connectionTimeout,
socketTimeout,
allowInsecure);
}