Besides what Corion said Re: Trying to decode JSON streaming from a website, your __data__stream starts with a [ and that goes with

#Look for everything past the first JSON pointer
$p->set_jsonpointer(["/^"]);
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But your socket stream doesnt seem too. Possibly

$p->feed('[');
while (my $line = <$cl>) {
...
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would help

or MAYBE if you drop $p->set_jsonpointer(["/^"]); you wont need to prefeed it or the inserted commas, dunnno