interface TraceStateInterface

interface TraceStateInterface {
    
    /**
     * Return a new TraceState object that inherits from this TraceState
     * and contains the given key value pair.
     *
     * @return TraceStateInterface
     */
    public function with(string $key, string $value) : TraceStateInterface;
    
    /**
     * Return a new TraceState object that inherits from this TraceState
     * without the given key value pair.
     *
     * @return TraceStateInterface
     */
    public function without(string $key) : TraceStateInterface;
    
    /**
     * Return the value of a given key from this TraceState if it exists
     *
     * @return string|null
     */
    public function get(string $key) : ?string;
    
    /**
     * Get the list-member count in this TraceState
     *
     * @return int
     */
    public function getListMemberCount() : int;
    
    /**
     * Returns the concatenated string representation.
     *
     * @param int|null $limit maximum length of the returned representation
     * @return string the string representation
     *
     * @see https://www.w3.org/TR/trace-context/#tracestate-limits
     */
    public function toString(?int $limit = null) : string;
    
    /**
     * Returns a string representation of this TraceSate
     */
    public function __toString() : string;

}