Add support for merged inverted output and error streams of remote process

Hello!

I want to merge output and error streams of remote process as java.lang.ProcessBuilder#redirectErrorStream(true) does.

If I set output and error streams;

channelExec.setOut(mergedOutputStream);
channelExec.setErr(mergedOutputStream);
channelExec.open.verify();

Then, ChannelExec#getInvertedOut() and ChannelExec#getInvertedErr() return null.

If I don't set output and error streams;

//channelExec.setOut(mergedOutputStream);
//channelExec.setErr(mergedOutputStream);
channelExec.open.verify();

Then, ChannelExec#getInvertedOut() and ChannelExec#getInvertedErr() return not null. But, streams are not merged.

How can I merge output and error streams of remote process ?

Thanks in advance!