Pipes example is a bit misleading w.r.t. wc processing.

[kareled]

Hello,

    // Because `stdin` does not live after the above calls, it is `drop`ed,
    // and the pipe is closed.
    //
    // This is very important, otherwise `wc` wouldn't start processing the
    // input we just sent.

the second part of the comment is a bit misleading since from the time we start wc, it processes data immediately. We need to close the pipe in order
to actually enforce wc to know its end of its business hence printing the sums to the output.