/**
* **IMPORTANT:** All of the following examples apply to Amp\Artax\Request *and* Amp\Artax\Response.
*
* Headers are stored with case-insensitive keys (as per RFC 2616 Sec4.2). You can access and
* assign message headers in requests/responses without worrying about case. Assigning headers is
* accomplished using Message::setHeader() which will clear any previously assigned values for the
* same header (regardless of field case):
*/
$request->setHeader('Content-Type', 'application/octet-stream');
assert($request->hasHeader('CONTENT-TYPE'));
// true
assert($request->hasHeader('CoNtEnT-tYpE'));
// true
assert($request->hasHeader('content-type'));
// true
assert($request->getHeader('conTENT-tyPE')[0] === 'application/octet-stream');
// true
$request->setHeader('CONTENT-TYPE', 'text/plain');
assert($request->getHeader('Content-Type')[0] === 'text/plain');
// true
/**
* You can assign multiple header lines by passing an array of scalar values as the header value.
* When sent by Amp\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']);
/**
