PHPMailer\PHPMailer

SMTP::setDebugOutput │ public │ WP 1.0

Set debug output method.

Method of the class: SMTP{}

No Hooks.

Returns

null. Nothing (null).

Usage

$SMTP = new SMTP();
$SMTP->setDebugOutput( $method );
$method(string|callable)
The name of the mechanism to use for debugging output, or a callable to handle it.
Default: 'echo'

SMTP::setDebugOutput() code WP 7.0

wp-includes/PHPMailer/SMTP.php 
public function setDebugOutput($method = 'echo')
{
    $this->Debugoutput = $method;
}