azure-storage-common/src/Common/Internal/Serialization/MessageSerializer.php
private static function serializeHeaders(array $headers)
    {
        $resultString = "Headers:\n";
        foreach ($headers as $key => $value) {
            $resultString .= sprintf("%s: %s\n", $key, $value[0]);
        }

        return $resultString;
    }
private static function serializeHeaders(array $headers)
    {
        $resultString = "Headers:\n";
        foreach ($headers as $key => $value) {
            $resultString .= sprintf("%s: %s\n", $key, $value[0]);
        }

        return $resultString;
    }
Serialize the message headers.

@param  array  $headers The headers to be serialized.

@return string