Good question. The others explained it well already but here is another hint. (You weren't actually passing a reference is why it didn't work.)

use strict;
use warnings;

my $data = {status=>"ok",'message-type'=>"member",'message-version'=>"
+1.0.0"};

my $result_hr;
ref($result_hr) ? print "ref($result_hr)\n" : print "\$result_hr is no
+t a reference.\n" ;
$result_hr = {};
ref($result_hr) ? print "ref($result_hr)\n" : print "\$result_hr is no
+t a reference.\n" ;

__DATA__
$result_hr is not a reference.
ref(HASH(0x3ddb70))
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