src/vs/workbench/services/workingCopy/common/storedFileWorkingCopyManager.ts/StoredFileWorkingCopyManager/canDispose
class StoredFileWorkingCopyManager:	canDispose(workingCopy: IStoredFileWorkingCopy<M>): true | Promise<true> {

		// Quick return if working copy already disposed or not dirty and not resolving
		if (
			workingCopy.isDisposed() ||
			(!this.mapResourceToPendingWorkingCopyResolve.has(workingCopy.resource) && !workingCopy.isDirty())
		) {
			return true;
		}

		// Promise based return in all other cases
		return this.doCanDispose(workingCopy);
	}