OptionalbackendRequested backend; auto tries WebGPU, WASM, then JavaScript.
OptionalcounterInitial Philox block counter; defaults to zero and must be a non-negative safe integer.
OptionalstreamUnsigned 32-bit stream identifier; defaults to zero.
Optionaltimestamp_Request timestamp-query support when creating the WebGPU device.
Backend and initial stream position for accelerated Philox.