BSF_Analytics::handle_optin_optout()

		public function handle_optin_optout() {

			if ( ! current_user_can( 'manage_options' ) ) {
				return;
			}

			$source = isset( $_GET['bsf_analytics_source'] ) ? sanitize_text_field( wp_unslash( $_GET['bsf_analytics_source'] ) ) : '';

			if ( ! isset( $_GET[ $source . '_analytics_nonce' ] ) ) {
				return;
			}

			if ( ! wp_verify_nonce( sanitize_text_field( wp_unslash( $_GET[ $source . '_analytics_nonce' ] ) ), $source . '_analytics_optin' ) ) {
				return;
			}

			$optin_status = isset( $_GET[ $source . '_analytics_optin' ] ) ? sanitize_text_field( wp_unslash( $_GET[ $source . '_analytics_optin' ] ) ) : '';

			if ( 'yes' === $optin_status ) {
				$this->optin( $source );
			} elseif ( 'no' === $optin_status ) {
				$this->optout( $source );
			}

			wp_safe_redirect(
				esc_url_raw(
					remove_query_arg(
						array(
							$source . '_analytics_optin',
							$source . '_analytics_nonce',
							'bsf_analytics_source',
						)
					)
				)
			);
		}