🚀 go-pugleaf

First, it doesn't return "void", it returns the event queued up by
"im_EnqueueEvent" to cause the specified function to be called.

Second, and more importantly, the function does *not* get called on the
next interaction, at least under X11.  The problem appears to be that
the event isn't triggered until the specified time increment has
occurred, so it never gets moved to the "pendingInteractionEvents"
queue, and thus never gets seen by the main interaction loop.

Is this intentional?  As I read the ATK documentation, the event queued
up by "im_SetInteractionEvent" should occur either on the next user
interaction or after the specified timeout, whichever comes first.  This
is definitely not happening, as can be attested to by the fact that, if
you type ^G and get the "Cancelled." message, the "Cancelled." message
stays on the message line until replaced by some other message.