/** Generate 32-char hex trace ID. */
export declare function newTraceId(): string;
/** Generate 16-char hex span ID. */
export declare function newSpanId(): string;
/** Convert millisecond epoch to nanosecond epoch string. */
export declare function msToNanoStr(ms: number): string;
/** Calculate duration in nanoseconds between two ms timestamps. */
export declare function durationNanoStr(startMs: number, endMs: number): string;
/** Calculate duration in milliseconds. */
export declare function durationMs(startMs: number, endMs: number): number;
/**
 * Best-effort local IPv4 address for the CLS `sourceIp` field.
 *
 * Falls back to loopback rather than the hostname: the CLS SDK requires a
 * non-empty value but never validates its format, so a hostname would be stored
 * as a malformed IP with no error anywhere.
 */
export declare function getLocalIp(): string;
/** Safe JSON stringify. */
export declare function safeStringify(value: unknown): string;
/** Convert any value to string for CLS attribute. */
export declare function toAttrString(value: unknown): string;
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