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When the cl_khr_priority_hints extension is available (OpenCL 2.1 and later), priority hints can be used by passing one of the three priority levels supported`clCreateCommandQueueWithProperties`.

Adding support is straightforward (just need to check API and device support), but we should also evaluate the platform support too when/before implementing it.

Ref: https://www.khronos.org/registry/OpenCL/specs/2.2/html/OpenCL_Ext.html#cl_khr_priority_hints