A check is performed to see if the given key is unique in the map which
means that a number of key comparisons equal to the current number of
elements in the map is made.
If the key already exists in map, or the map's capacity is exhausted, the
insertion will fail. If insertion fails, the map doesn't take ownership of
key and value.
If the insertion is successful, map takes ownership of key and value.
Inserts the given key-value pair into the map.
A check is performed to see if the given key is unique in the map which means that a number of key comparisons equal to the current number of elements in the map is made.
If the key already exists in map, or the map's capacity is exhausted, the insertion will fail. If insertion fails, the map doesn't take ownership of key and value.
If the insertion is successful, map takes ownership of key and value.