Even if one of downstream d3d11 elements can support dynamic-usage memory,
another one might not support it. Also, to support dynamic-usage,
both upstream and downstream d3d11device must be the same object.
In some cases, rendering and dxgi (e.g., swapchain) APIs should be
called from window message pump thread, but current design (dedicated d3d11 thread)
make it impossible. To solve it, change concurrency model to locking based one
from single-thread model.