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ForceLang, 155 bytes

def s set
s d datetime
s z string.char 8
s i 1
label 0
s z z+z
if z.len=16
goto 1
goto 0
label 1
io.write z
io.write d.toTimeString d.now()
d.wait 9
goto 1

datetime.toTimeString is backed in the reference implementation by Java's DateFormat.getTimeInstance(), which is locale-dependent, so you can set your default system locale to one that uses 24-hour time.