src/vs/platform/userDataSync/common/abstractSynchronizer.ts/AbstractSynchroniser/resolvePreviewContent
class AbstractSynchroniser:	protected async resolvePreviewContent(uri: URI): Promise<string | null> {
		const syncPreview = this.syncPreviewPromise ? await this.syncPreviewPromise : null;
		if (syncPreview) {
			for (const resourcePreview of syncPreview.resourcePreviews) {
				if (this.extUri.isEqual(resourcePreview.acceptedResource, uri)) {
					return resourcePreview.acceptResult ? resourcePreview.acceptResult.content : null;
				}
				if (this.extUri.isEqual(resourcePreview.remoteResource, uri)) {
					return resourcePreview.remoteContent;
				}
				if (this.extUri.isEqual(resourcePreview.localResource, uri)) {
					return resourcePreview.localContent;
				}
				if (this.extUri.isEqual(resourcePreview.baseResource, uri)) {
					return resourcePreview.baseContent;
				}
			}
		}
		return null;
	}