Write To stdin of ChildProcess

I want to pipe some input into the stdin of a child process. In a Unix shell this can be achieved with 

echo "some input" | mytool -i - --option

(for example)

The ChildProcess class supports reading the stdout and stderr streams, but I cannot find a way to write to stdin. Is there maybe a way of achieving it using InterprocessConnection for example? If yes, would you mind sketching out the way of doing it roughly, because I am not sure how to do it? Thanks. 

Any hints where I could start looking myself?

ChildProcess only supports reading, not writing, but you could use an InterprocessConnection if you're just trying to establish a comms channel between the processes.