Model calculation is not able to read features from stdin

[vpd]

There is currently a disappointing exception when trying to read features from stdin:
(TCatboostException) catboost/libs/data/load_data.cpp:181: pool file is not found -

Streaming calculation is quite a valuable feature when running a calculation on a large stream of data generated on fly because otherwise there is an inevitable cost of disk i/o operations and process start/termination.

[annaveronika]

We don't support reading pool from stdin, we are currently fixing the documentation.

[vpd]

Can one hope that it would be supported in future?

[annaveronika]

Ok, we'll do it.

[annaveronika]

Actually it's a good idea for contribution, so I'm adding a help wanted and good first issue labels.

[stohirov]

Hello @annaveronika. please, let me know if somebody is working on this issue.
I will provide a PR for this issue as soon as I am free.

just in case: @andrey-khropov