code: func (ctx *BatchedContext) MemAlloc(bytesize int64) (retVal DevicePtr, err error) {
  	fn := &fnargs{
  		fn:   C.fn_mallocD,
  		size: C.size_t(bytesize),
  	}
  	c := call{fn, true}
  	return ctx.enqueue(c)
  }
docs: // MemAlloc allocates memory. It is a blocking call.