Noptin_Mailer::send( $to,  $subject,  $email )

	public function send( $to, $subject, $email ) {

		// Don't send if email address is invalid.
		if ( ! is_email( $to ) ) {
			return false;
		}

		// Hooks before an email is sent.
		do_action( 'before_noptin_sends_email', $to, $subject, $email, $this );

		/*
		 * Allow to filter data on per-email basis.
		 */
		$data = apply_filters(
			'noptin_mailer_email_data',
			array(
				'to'          => $to,
				'subject'     => $subject,
				'email'       => $email,
				'headers'     => $this->get_headers(),
				'attachments' => array(),
			),
			$this,
			$this->mailer_data
		);

		$data               = wp_unslash( $data );
		$this->wp_mail_data = $data;

		// Attach our own hooks.
		$this->before_sending();

		// Prepare the sending function.
		$sending_function = apply_filters( 'noptin_mailer_email_sending_function', 'wp_mail', $this );

		// Send the actual email.
		$result = call_user_func(
			$sending_function,
			$data['to'],
			html_entity_decode( $data['subject'], ENT_QUOTES, get_bloginfo( 'charset' ) ),
			$data['email'],
			$data['headers'],
			$data['attachments']
		);

		// If the email was not sent, log the error.
		if ( empty( $result ) ) {
			log_noptin_message(
				sprintf(
					/* Translators: %1$s Email address, %2$s Email subject. */
					__( 'Failed sending an email to %1$s with the subject %2$s', 'newsletter-optin-box' ),
					sanitize_email( $data['to'] ),
					wp_specialchars_decode ( $data['subject'] )
				)
			);
		}

		// Remove our hooks.
		$this->after_sending();

		// Hooks after an email is sent.
		do_action( 'after_noptin_sends_email', $to, $subject, $email, $this, $result );

		$this->wp_mail_data = null;

		return $result;
	}