Looks up the mapping for key or adds one if not found.
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().
an array slicing the value buffer mapped to by the specified key. If
added outputs true, the value is unspecified and the caller should
set the value as desired.
Out:
The returned array is never null and has the length V.
Looks up the mapping for key or adds one if not found.
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().