Description:
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array getallheaders ( void )
array apache_request_headers ( void )

... We already have many ways to get some header if need,
apache_request_headers, getallheaders are the same...
$_SERVER, $_REQUEST, $_ENV, $GLOBALS (if not unset), etc..

Is full of arrays all over the place and there is no way to get some variable without using "isset" (aside: I think isset is the most used word in PHP)
I know we can use $_SERVER['whatever'] ?? null
but for once whould be nice to have a function that return null for us
by default in case it not exists..

My request is to add a new parameter to any of that function
getallheaders/apache_request_headers($header_name = null),
or create a new function, i.e. getheader(string $name = null/void)
will be much faster if is implemented in the core, and easier to work with..
if ('php.net' = getheader('host'))
    do something...
instead of
$headers = getallheaders( );
if (isset($headers['Host']) && $headers['Host'] == 'php.net')
    do something...

you got the idea... Thank you