/**
* You can assign multiple header lines by passing an array of scalar values as the header value.
* When sent by Artax the relevant portion of the raw request message for the below set of headers
* will look like this:
*
* Cookie: cookie1=val1
* Cookie: cookie2=val2
* Cookie: cookie3=val3
*/
$request->setHeader('Cookie', ['cookie1=val1', 'cookie2=val2', 'cookie3=val3']);
/**
* Append headers without overwriting using Message::appendHeader():
*/
assert(count($request->getHeader('cookie')) === 3);
// true
$request->appendHeader('Cookie', 'cookie4=val4');
assert(count($request->getHeader('Cookie')) === 4);
// true
/**
* You may set multiple headers at one time via $request->setAllHeaders():
*/
$request->setAllHeaders(['X-My-Header' => 'some value', 'Accept' => '*/*', 'Cookie' => ['cookie1=val1', 'cookie1=val2']]);
/**
* You can remove a previously assigned header value using Message::removeHeader(). Once again,
* the header field name is case-insensitive:
*/
$request->removeHeader('cookie');
assert(!$request->hasHeader('Cookie'));
// true
/**
* If you attempt to retrieve a non-existent header Artax will throw a DomainException:
