Function store_association_state 

pub fn store_association_state(
    context: &impl IdentityContext,
    sequence_id: i64,
    state: &AssociationState,
) -> Result<(), IdentityUpdateError>

Store the association state of an inbox at sequence_id in the client’s cache. In the same write, read the newest state the client already holds for the inbox, and buffer handle.changed when the stored state changes its display handle. The event is emitted after the write commits.