/// export declare type AssignableRef = { bivarianceHack(instance: ValueType | null): void; }['bivarianceHack'] | React.MutableRefObject; export declare function useForkedRef(...refs: (AssignableRef | null | undefined)[]): (node: any) => void; export declare function assignRef(ref: AssignableRef | null | undefined, value: any): void; export declare function isFunction(value: any): value is Function;