The buckets storage area is the primary hash table of capacity elements.
To search some key,
the first access is done in buckets using the remainder of the division of the key hash_code
by capacity. In order to try to avoid clashes, capacity is always a prime number (selected
using HASHED_CAPACITY).
Actually, this feature is useful only
when the type of values (the type V_) is a reference type, to avoid using has just
followed by at to get the corresponding value with the very best performances.
If there is as yet no key k in the dictionary,
enter it with item v. Otherwise overwrite the item associated with key k.
As the put procedure actually uses is_equal, you may consider to use fast_put for expanded
objects as well while trying to get the very best performances.
Remove entry k (which may exist or not before this call).
As the remove procedure actually uses is_equal, you may consider to use fast_remove for expanded
objects as well while trying to get the very best performances.