/**
 * Singleton gate for stream debug logging.
 *
 * WireAdapter reads this on every stream() call, so runtime toggles
 * (via /settings debug-stream on|off) take effect on the next request
 * without recreating provider instances.
 *
 * When enabled, WireAdapter accumulates per-chunk stats and pushes them
 * through a registered callback. In CLI (non-TUI) mode the default
 * callback writes a compact status line to stderr. The TUI replaces
 * the callback with one that dispatches to its reducer so the debug
 * info renders inside Ink's StatusBar line 3 instead of bypassing it.
 *
 * The CLI boot path seeds this from config.debugStream at startup.
 */
export interface DebugStreamStats {
    /** Monotonic chunk counter, resets per-stream. */
    chunkCount: number;
    /** Bytes of the most recent chunk. */
    lastChunkSize: number;
    /** Millisecond delta since the PREVIOUS chunk (reveals think gaps). */
    lastDeltaMs: number;
    /** Cumulative bytes received for this stream. */
    totalBytes: number;
    /** ISO timestamp of the most recent chunk. */
    lastChunkAt: string;
}
export type DebugStreamCallback = (stats: DebugStreamStats) => void;
/** Check whether raw SSE stream debugging is currently active. */
export declare function isDebugStreamEnabled(): boolean;
/** Flip the stream debug flag at runtime. Persisted separately via ConfigStore. */
export declare function setDebugStreamEnabled(enabled: boolean): void;
/**
 * Register a callback that receives THROTTLED debug-chunk stats (~5 Hz).
 * WireAdapter calls `pushDebugChunkStats()` on every raw chunk; this module
 * batches them and calls `cb` at most once per THROTTLE_MS.
 *
 * Pass `null` to restore the default stderr behaviour.
 */
export declare function setDebugStreamCallback(cb: DebugStreamCallback | null): void;
/**
 * Called by WireAdapter on every raw chunk. Not throttled — call it as
 * often as chunks arrive; it's cheap (a few integer assigns + a debounced
 * setTimeout). The registered callback receives aggregated stats at most
 * once per THROTTLE_MS.
 */
export declare function pushDebugChunkStats(bytes: number, deltaMs: number): void;
/**
 * Default callback: write a compact status line to stderr (used in CLI /
 * headless mode where Ink isn't painting the terminal).
 */
export declare function defaultDebugStreamCallback(stats: DebugStreamStats): void;
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