Can the function of sending custom strings after XXX seconds of idleness be added?

Now the SSH session setting has the function of "sending empty packets to keep the session active", but in some Jump Server environments, this request is not responded. Can the function of sending custom strings after XXX seconds of idleness be added? For example, send a space every XxX seconds, thank you!

Review the SSH session keepalive setting and its existing empty-packet behavior first. Determine how idle time is measured and where a configurable custom string could be sent; done means the setting supports sending that string after the requested idle interval without disrupting the session.

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