Ensures the dictionary has enough space to store the requested number of key/object pairs.
The total number of key/object pairs the dictionary should be able to store.
The new capacity of the dictionary, which may be different from the number requested (if smaller, reallocation of storage failed).
This function immediately resizes the dictionary, if necessary, to accommodate at least
new key/object pairs. If
new is not greater than the current capacity, or if an allocation error occurs, the original capacity is returned.
There is no way to reduce the capacity of an OSDictionary.