mgpuGetWGPUBufferHandle function
Returns the Emscripten integer handle for a WGPUBuffer inside buf.
Pass to getWebGpuJsObject from webgpu_interop.dart to get the JS GPUBuffer.
Implementation
int mgpuGetWGPUBufferHandle(MGPUBuffer buf) =>
_mgpuGetWGPUBufferHandleJs(buf).toDartDouble.toInt();