example.      86400   IN  SOA     ns1 admin 2018031900 (
			     1800 900 604800 86400 )
	      86400   IN  NS      ns1
	      86400   IN  NS      ns2
	      86400   IN  ZONEMD  2018031900 1 1 (
			          31cefb03814f5062
			          ad12fa951ba0ef5f
			          8da6ae354a415767
			          246f7dc932ceb1e7
			          42a2108f529db6a3
			          3a11c01493de358d )
ns1           3600    IN  A       203.0.113.63
ns2           3600    IN  AAAA    2001:db8::63
occluded.sub  7200    IN  TXT     "I'm occluded but must be digested"
sub           7200    IN  NS      ns1
duplicate     300     IN  TXT     "I must be digested just once"
duplicate     300     IN  TXT     "I must be digested just once"
foo.test.     555     IN  TXT     "out-of-zone data must be excluded"
non-apex      900     IN  ZONEMD  2018031900 1 1 (
			          616c6c6f77656420
			          6275742069676e6f
			          7265642e20616c6c
			          6f77656420627574
			          2069676e6f726564
			          2e20616c6c6f7765 )