getSize( target ) {

		const data = this.data;

		if ( data instanceof HTMLVideoElement ) {

			target.set( data.videoWidth, data.videoHeight );

		} else if ( data !== null ) {

			target.set( data.width, data.height, data.depth || 0 );

		} else {

			target.set( 0, 0, 0 );

		}

		return target;

	}
This starts at `0` and counts how many times {@link Source#needsUpdate} is set to `true`.

@type {number}
@readonly
@default 0