export type ConnectionState = 'OPEN' | 'CLOSING' | 'CLOSED';
export declare const CONNECTION_TRANSITIONS: Readonly<Record<ConnectionState, readonly ConnectionState[]>>;
export declare const PROTOCOL_DIAGNOSTIC_CAPACITY = 128;
export interface ConnectionCloseSnapshot {
    readonly code: number | null;
    readonly reason: null;
}
export type Deferred<T> = {
    readonly promise: Promise<T>;
    readonly resolve: (value: T) => void;
    readonly reject: (reason: unknown) => void;
};
export declare function deferred<T>(): Deferred<T>;