user_agent.php
public function setIdentity($host, $realm, $username, $password)
    {
        $this->authenticator->setIdentityForRealm($host, $realm, $username, $password);
    }
public function setIdentity($host, $realm, $username, $password)
    {
        $this->authenticator->setIdentityForRealm($host, $realm, $username, $password);
    }
Sets the identity for the current realm.

@param string $host        Host to which realm applies.
@param string $realm       Full name of realm.
@param string $username    Username for realm.
@param string $password    Password for realm.