protected final <T> T getAdvancedConfig(AdvancedConfig.Key<T> key) {
        return advancedConfig.get(key);
    }
Get the current value of an advanced config option.
@param key Key of value to get.
@param <T> Type of value to get.
@return Value if set, otherwise null.
aws-java-sdk-core/src/main/java/com/amazonaws/client/builder/AwsClientBuilder.java