Interface TextDocumentSynchronizationMiddleware

interface TextDocumentSynchronizationMiddleware {
    didChange?: NextSignature<TextDocumentChangeEvent, Promise<void>>;
    didClose?: NextSignature<TextDocument, Promise<void>>;
    didOpen?: NextSignature<TextDocument, Promise<void>>;
    didSave?: NextSignature<TextDocument, Promise<void>>;
    willSave?: NextSignature<TextDocumentWillSaveEvent, Promise<void>>;
    willSaveWaitUntil?: NextSignature<
        TextDocumentWillSaveEvent,
        Thenable<TextEdit[]>,
    >;
}