export interface ILogger {
    /**
     * Saves / sends a log message at INFO level.
     * @param message message to log
     * @param service name of service that generated the log message
     * @param position block height of current process
     */
    info(message: string, service?: string, position?: number): void;
    /**
     * Saves / sends a log message at WARN level.
     * @param message message to log
     * @param service name of service that generated the log message
     * @param position block height of current process
     */
    warn(message: string, service?: string, position?: number): void;
    /**
     * Saves / sends a log message at DEBUG level.
     * @param message message to log
     * @param service name of service that generated the log message
     * @param position block height of current process
     */
    debug(message: string, service?: string, position?: number): void;
    /**
     * Saves / sends a log message at ERROR level.
     * @param message message to log
     * @param service name of service that generated the log message
     * @param position block height of current process
     * @param stack error stack trace, if any
     */
    error(message: string, service?: string, position?: number, stack?: any): void;
}