Shared ownership of a single C array.
Tracks offset and length for each instance
allowing each owner to "view" a different
piece of the array.
Parts of shared_vector<T> which can work
for T=void are in shared_vector_base<T>.
Specializations shared_vector<void>
and shared_vector<const void> handle
un-typed arrays.
Allow casting to/from typed vector
Offsets and sizes of untyped vectors are tracked in
bytes. Therefore casting to types where sizeof(T)>1
is undefined if the offset is not a multiple of
sizeof(T).
3cd2bfdef0