public <T extends Serializable> T getExtraProperty(String key, Class<T> valueClass) {
        return valueClass.cast(extraProps.get(key));
    }
Gets a typed extra property.

@param <T>        type of the property value
@param key        key of the property
@param valueClass non-null Java class of the property value
@return typed extra property, could be null
clickhouse-data/src/main/java/com/clickhouse/data/ClickHouseDataProcessor.java