Indexed: If the value should be indexed.
The indexed property may be set for a null value. When indexed is true, stringValue is limited to 500 characters and the blob value is limited to 500 bytes. Input values by default have indexed set to true; however, you can explicitly set indexed to true if you want. (An output value never has indexed explicitly set to true.) If a value is itself an entity, it cannot have indexed set to true.