Set a tensor in a promise.

    $promise: A value of type !mlrt.promise. The underlying value must be a tensorflow tensor.
    $tensor: A tensorflow tensor.
  }];

  let arguments = (ins
    MlrtPromiseType:$promise,
    TFTensorType:$tensor
  );

  let assemblyFormat = "operands attr-dict";
}

def PromiseFutureOp: TensorflowMlrt_Op<"promise_future", []> {