Adds or updates a mapping from the specified key. Note that, if a new
mapping was added (added outputs true), the returned slice may reference
a previously removed value. If this is not desired, copy the desired
initial value into the sliced buffer returned by remove().
Adds or updates a mapping from the specified key. Note that, if a new mapping was added (added outputs true), the returned slice may reference a previously removed value. If this is not desired, copy the desired initial value into the sliced buffer returned by remove().