export interface ScannedMessage {
    /** The complete envelope bytes (header through the END frame). */
    readonly message: Uint8Array;
    /** Byte count buffered PAST the END frame — a §8.7 stream MUST end
     * exactly at the END frame's last byte, so any excess is a protocol
     * violation (pipelining) for the caller to act on. */
    readonly excess: number;
}
export declare class MessageStreamScanner {
    #private;
    /** True once any bytes were fed. */
    get started(): boolean;
    /**
     * Feed one chunk. Returns the completed message once the END frame is
     * fully buffered, `undefined` while more bytes are needed. Throws
     * `DecodeError` on an invalid envelope header (connection-fatal per
     * §8.7) and plain `Error` on use after completion.
     */
    push(chunk: Uint8Array): ScannedMessage | undefined;
}