Align mask?

[kvark]

From the implementation perspective, I can see how align mask would be more convenient. But from the API perspective in the Request, it's not very nice. For one, it's not clear if the mask is just supposed to be alignment - 1 or the !(alignment - 1) from the documentation. Would it be simpler to just receive the alignment and document that it has to be a power of 2?

[zakarumych]

I guess you're right that receiving alignment value would make API more intuitive.