src/vs/workbench/api/common/extHostLanguageFeatures.ts/ExtHostLanguageFeatures/$prepareTypeHierarchy
class ExtHostLanguageFeatures:	$prepareTypeHierarchy(handle: number, resource: UriComponents, position: IPosition, token: CancellationToken): Promise<extHostProtocol.ITypeHierarchyItemDto[] | undefined> {
		return this._withAdapter(handle, TypeHierarchyAdapter, adapter => Promise.resolve(adapter.prepareSession(URI.revive(resource), position, token)), undefined, token);
	}