02f100995e
https://github.com/flutter/flutter/issues/129392 Buffer allocations on worker threads can interefere with allocations on the main thread. Since all buffers that we allocate on the main thread are discarded after a frame, we can use a ring buffer of VmaPool objects with a linear allocate bit to get faster allocations. This works for buffers because they are likely to be suballocated, so we can continue to reuse the same memory over and over. Whereas most of our textures require dedicated allocations. In order to support this, we need the allocator to track an incrementing frame counter (actually this would probably be useful for the context to do in general, but we'll get there eventually). 
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