src/vs/workbench/services/textfile/common/textFileEditorModel.ts/TextFileEditorModel/updateLastResolvedFileStat
class TextFileEditorModel:	private updateLastResolvedFileStat(newFileStat: IFileStatWithMetadata): void {
		const oldReadonly = this.isReadonly();

		// First resolve - just take
		if (!this.lastResolvedFileStat) {
			this.lastResolvedFileStat = newFileStat;
		}

		// Subsequent resolve - make sure that we only assign it if the mtime is equal or has advanced.
		// This prevents race conditions from resolving and saving. If a save comes in late after a revert
		// was called, the mtime could be out of sync.
		else if (this.lastResolvedFileStat.mtime <= newFileStat.mtime) {
			this.lastResolvedFileStat = newFileStat;
		}

		// Signal that the readonly state changed
		if (this.isReadonly() !== oldReadonly) {
			this._onDidChangeReadonly.fire();
		}
	}