The current accessor implementation relies on the usual easy detail::shared_ptr_implementation but requires some painful magical Clang rewriting of lambda captures to use drt::accessor instead.
Instead, make a new accessor implementation split in 2 parts, a simple one visible by the device and a heavy shepherd one to manage the accessed resource that will be optimized away by the device compiler in a simpler and natural way.
So make the runtime more complex, but the device compiler simpler.
This is a first step toward solving #179