set Custom Attribute
Sets a custom attribute for the user. If an attribute with the same key already exists, its value will be updated. Setting a value to null is equivalent to calling removeCustomAttribute for that key.
Parameters
key
The name of the attribute to set. Cannot be null, empty, or the SDK-reserved __storyteller_followed_category_attribute_keys__ key.
value
The value of the attribute. If null, the attribute will be removed.
Throws
if key is reserved for SDK use.