Returns an instance of
T calculated by summing all instances in iter in one pass.
Returns an instance of
T calculated by summing all instances in iter in one pass. Returns None if
iter is empty, else Some[
T].
None if iter is empty, else an option value containing the summed
T
Override if there is a faster way to compute this sum than iter.reduceLeftOption using plus.
In some legacy cases, we have implemented Rings where we lacked the full laws. This allows you to be precise (only implement the structure you have), but unsafely use it as a Ring in legacy code that is expecting a Ring.