import { WritableSignal } from "@angular/core";
export interface SdWritableSignal<T> extends WritableSignal<T> {
    $mark(): void;
}
export declare function $signal<T>(): SdWritableSignal<T | undefined>;
export declare function $signal<T>(initialValue: T): SdWritableSignal<T>;
export declare function toSignal<T>(sig: WritableSignal<T>): SdWritableSignal<T>;