x/crypto/salsa20: Stream mode instead of message mode

[kub...@ipn.io]

The docs for salsa20 in x/crypto say (https://godoc.org/golang.org/x/crypto/salsa20):

Salsa20 differs from many other stream ciphers in that it is message orientated rather than byte orientated. Keystream blocks are not preserved between calls, therefore each side must encrypt/decrypt data with the same segmentation.

I would like to ask if there is anything that prevents existence of stream mode in salsa20? I could not find any justification of limiting the implementation to just this mode.
 

~ Jakub "Kubuxu" Sztandera