*<Null safety>*
int alloc (int size)
Implementation
int alloc(int size) {
if (_nextOutOfLineDepth > _maxOutOfLineDepth) {
throw FidlError('Exceeded maxOutOfLineDepth',
FidlErrorCode.fidlExceededMaxOutOfLineDepth);
}
_nextOutOfLineDepth++;
int offset = _extent;
_claimMemory(_align(size));
return offset;
}