Description:
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It seems that a cloned NumberFormatter object loses attributes set to the original object.

I tried setting attributes in both NumberFormatter::setTextAttribute() and NumberFormatter::setAttribute() and they were not transferred to the cloned object.

It may affect other intl object that has custom attributes.

Test script:
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$fmt = NumberFormatter::create('en', NumberFormatter::DURATION);
$fmt->setTextAttribute(NumberFormatter::DEFAULT_RULESET, "%with-words");

$fmt_clone = clone $fmt;

var_dump($fmt->getTextAttribute(NumberFormatter::DEFAULT_RULESET), $fmt_clone->getTextAttribute(NumberFormatter::DEFAULT_RULESET));

$fmt = NumberFormatter::create('en', NumberFormatter::DECIMAL);
$fmt->setAttribute(NumberFormatter::FRACTION_DIGITS, 2);

$fmt_clone = clone $fmt;

var_dump($fmt->getAttribute(NumberFormatter::FRACTION_DIGITS), $fmt_clone->getTextAttribute(NumberFormatter::FRACTION_DIGITS));


Expected result:
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string(9) "%with-words"
string(9) "%with-words"
int(2)
int(2)

Actual result:
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string(11) "%with-words"
string(9) "%duration"
int(2)
bool(false)