How to read from stdout and, without waiting for the end, redirect the output?

Question

go

The task is a logical continuation of How to write stdout to a buffer and read from it line by line?

The bottom line is that https://play.golang.org/p/aryjjfUZEmt is waiting for the end of the output. Until this happens, nothing is sent to the broker (in this example, for simplicity, to the screen).
I need not to wait and, as soon as the withdrawal is received, send them to the broker.

I have the main snag with line feeds, because when you receive an array of bytes, write it to the buffer, and another reader can pick it up and analyze the line feeds (using a scanner).

Added:
For an example of the effect, instead cmd := exec.Command("ls", "/etc")of (line 24 from the code above) I took from https://gobyexample.com/tickersand compiled the code for a program that outputs data to stdout not immediately, but gradually using a timer. As a result, it turns out that until the process is completed, in the above example, there will be no sending by rows.

Added:
Updated the code with my attempt.