fn getOrPutAssumeCapacity(self: *Self, key: K) GetOrPutResult

If there is an existing item with key, then the result Entry pointer points to it, and found_existing is true. Otherwise, puts a new item with undefined value, and the Entry pointer points to it. Caller should then initialize the value (but not the key). If a new entry needs to be stored, this function asserts there is enough capacity to store it.

Parameters

self: *Self,
key: K,