Once the memory for incoming data is taken from an allocator we can implement
different approaches to manage that memory:

- The allocator is global, allowing applications to keep the incoming buffer
even after the upcall has finished.
- The allocator is TSS, giving maximum performance for applications that do not
wish to preserve the buffer after the upcall.
- The allocator is a TSS cache for a global memory pool, this tries to strike a
balance, by practically eliminating the locking on each allocator/deallocation.
Some strategy is required to return the memory to the global pool, consider, for
example, an application that will always allocate memory from one thread and
deallocate it in another thread.