Function try_leave 

pub async fn try_leave(
    db: &SqlitePool,
    group_id: Uuid,
    user_id: Uuid,
) -> Result<bool, Error>

Atomically remove the calling user from a group. If the caller is an owner the delete only fires when at least one other owner exists, so two concurrent leaves by the last two owners cannot both succeed. Returns true if a row was deleted.

Errors

Returns Error::Database on delete failure.