import type { AdaptiveConcurrencyConfig, FailureClassification, RouterOrderingToken } from "./types.js";
export declare const MAX_ROUND_ROBIN_POOLS = 1024;
export declare const MAX_ROUND_ROBIN_POOL_KEY_CHARS = 1048576;
export declare const MAX_WAITERS_PER_KEY = 10000;
export declare const ADMISSION_ORDERING_TOKEN_RE: RegExp;
export declare function roundRobinPoolKey(candidates: readonly {
    fullIndex: number;
}[]): string;
export interface AdmissionEntry {
    adaptiveConcurrency?: boolean | AdaptiveConcurrencyConfig;
    healthKey?: string;
    maxConcurrency?: number;
}
export interface AdmissionSnapshot {
    adaptive: boolean;
    increaseAfterSuccesses?: number;
    index: number;
    inFlight: number;
    limit?: number;
    max?: number;
    min?: number;
    successes?: number;
    waiting: number;
}
export declare class RouterConcurrencyError extends Error {
    readonly code = "concurrency_exhausted";
    readonly logicalId: string;
    constructor(logicalId: string);
}
export interface AdaptiveState {
    increaseAfterSuccesses: number;
    lastOutcomeOrderingToken?: RouterOrderingToken;
    lastOutcomeStartedAt?: number;
    limit: number;
    max: number;
    min: number;
    successes: number;
}
export declare function normalizedAdaptiveState(value: unknown): AdaptiveState | undefined;
export interface Waiter {
    acquire: () => number | undefined;
    resolve: (value: number | undefined) => void;
}
export declare function isValidWaiterSlot(value: unknown): value is number;
export declare function isCongestionFailure(failure: FailureClassification | undefined): boolean;
export declare function staleAdaptiveOutcome(state: AdaptiveState, attemptStartedAt: number | undefined, orderingToken: RouterOrderingToken | undefined): boolean;
export declare function compareAdaptiveOrderingTokens(left: string, right: string): number;
export declare function retainAdaptiveOutcomeOrder(state: AdaptiveState, attemptStartedAt: number | undefined, orderingToken: RouterOrderingToken | undefined): void;
export declare function abortReason(signal: AbortSignal | undefined): unknown;
export declare function isSignalAborted(signal: AbortSignal | undefined): boolean;
export declare function captureUsableWaiter(value: unknown): Waiter | undefined;
export declare class AdmissionRegistry {
    readonly adaptiveStates: Map<string, AdaptiveState>;
    readonly configurations: Map<string, string>;
    readonly inFlightCounts: Map<string, number>;
    readonly waiters: Map<string, Waiter[]>;
}