public static function getFormattedHeaders($headers)
{
$formattedHeaders = array();
$combinedHeaders = array_change_key_case(array_merge(self::$defaultHeaders, (array) $headers));
foreach ($combinedHeaders as $key => $val) {
$formattedHeaders[] = self::getHeaderString($key, $val);
}
if (!array_key_exists('user-agent', $combinedHeaders)) {
$formattedHeaders[] = 'user-agent: unirest-php/2.0';
}
if (!array_key_exists('expect', $combinedHeaders)) {
$formattedHeaders[] = 'expect:';
}
return $formattedHeaders;
}