/**
 * Adaptive, application-path connection measurement for preflight.
 *
 * The transport is deliberately injectable: production uses HTTP requests to
 * the ProctorKit API while tests supply deterministic samples without moving
 * real bytes. The result distinguishes representative throughput from a
 * conservative lower percentile; pass/fail policy should use the conservative
 * value so one unusually fast request cannot hide an unstable connection.
 */
export interface ConnectionTransferSample {
    bytes: number;
    durationMs: number;
    mbps: number;
}
export interface ConnectionProbeTransport {
    latency(timeoutMs: number): Promise<number>;
    download(bytes: number, timeoutMs: number): Promise<ConnectionTransferSample>;
    upload(bytes: number, timeoutMs: number): Promise<ConnectionTransferSample>;
}
export interface ConnectionQualityOptions {
    /** Hard ceiling for latency + download + upload together. Default: 10s. */
    maxDurationMs?: number;
    /** Number of idle round-trip samples. Default: 5. */
    latencySamples?: number;
    /** Adaptive payload ladder. Default targets readiness around 2 Mbps. */
    payloadSizes?: number[];
    /** A transfer lasting this long is considered representative. Default: 750ms. */
    stableSampleMs?: number;
    /** Injectable monotonic clock. */
    now?: () => number;
}
export interface ConnectionQualityResult {
    downloadMbps: number | null;
    uploadMbps: number | null;
    conservativeDownloadMbps: number | null;
    conservativeUploadMbps: number | null;
    latencyMs: number | null;
    jitterMs: number | null;
    downloadSamples: ConnectionTransferSample[];
    uploadSamples: ConnectionTransferSample[];
    latencySamples: number[];
    totalDurationMs: number;
}
export interface HttpConnectionProbeOptions {
    downloadUrl: string;
    uploadUrl: string;
    headers?: Record<string, string>;
    fetchFn?: typeof fetch;
    now?: () => number;
}
/** Measure connection quality without letting a stalled transport freeze the UI. */
export declare function measureConnectionQuality(transport: ConnectionProbeTransport, options?: ConnectionQualityOptions): Promise<ConnectionQualityResult>;
/** Build the real browser transport for the ProctorKit network-test routes. */
export declare function createHttpConnectionProbe(options: HttpConnectionProbeOptions): ConnectionProbeTransport;
export declare function transferSample(bytes: number, durationMs: number): ConnectionTransferSample;
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