bsl::unordered_multiset::erase

Remove from this unordered multiset all value_type objects that are equivalent to the specified key, if they exist, and return the number of object erased; otherwise, if there are no value_type objects equivalent to key, return 0 with no other effect. This method invalidates only iterators and references to the removed element and previously saved values of the end() iterator, and preserves the relative order of the elements not removed.