How to do streaming packaging on LZMA (7zip SDK)?

Question

Data archiving

Packing data like this

CArhiv oArhiv;
oArhiv.open("file.arc")
oArhiv.write("123",3); // 1-ая порция данных
oArhiv.write("12345",5); // 2-ая порция данных
oArhiv.write("12",2); // 3-ая порция данных
oArhiv.close("");

I'm using 7zip SDK , but I can't figure out how to do stream packing with LZMA. the example 7zip\C\Util\Lzma\LzmaUtil.c uses the function

LzmaEnc_Encode(enc, outStream, inStream, NULL, &g_Alloc, &g_Alloc)

which packs a stream into a stream. I do not quite understand how to add data to the output stream in portions?