@Override
    public String guessRegionFromEndpoint(String host, String serviceHint) {
        return AwsHostNameUtils.parseRegion(host, serviceHint);
    }
A default implementation of {@link RegionFromEndpointResolver} that only considers what is available in the host
name itself.

@see AwsHostNameUtils#parseRegion(String, String)
aws-java-sdk-core/src/main/java/com/amazonaws/util/endpoint/DefaultRegionFromEndpointResolver.java