Why the rt() function set the http header ?

[borgogelli]

Hi Sir

we use the @rt() function inside our Slim webapp to log data to file.
The problem is that the same function set the http header with the following statement:
header('Content-Type: text/plain; charset=utf-8'); (file ref.php, line 73)
That goes in conflict with our webapp which should serve html content.

Any advice ?
Thank you