Automattic / jetpack

		// Check if the nbf if it is defined. This is the time that the

		// token can actually be used. If it's not yet that time, abort.

		if ( isset( $payload->nbf ) && $payload->nbf > ( $timestamp + static::$leeway ) ) {

			throw new BeforeValidException(

				'Cannot handle token prior to ' . gmdate( DateTime::ISO8601, $payload->nbf )

			);

		}

		// Check that this token has been created before 'now'. This prevents

		// using tokens that have been created for later use (and haven't

		// Check that this token has been created before 'now'. This prevents

		// using tokens that have been created for later use (and haven't

		// correctly used the nbf claim).

		if ( isset( $payload->iat ) && $payload->iat > ( $timestamp + static::$leeway ) ) {

			throw new BeforeValidException(

				'Cannot handle token prior to ' . gmdate( DateTime::ISO8601, $payload->iat )

			);

		}

		// Check if this token has expired.

		if ( isset( $payload->exp ) && ( $timestamp - static::$leeway ) >= $payload->exp ) {