interface ReadableSpanInterface

interface ReadableSpanInterface {
    public function getName() : string;
    public function getContext() : API\SpanContextInterface;
    public function getParentContext() : API\SpanContextInterface;
    public function getInstrumentationScope() : InstrumentationScopeInterface;
    public function hasEnded() : bool;
    
    /**
     * Returns an immutable representation of this instance.
     */
    public function toSpanData() : SpanDataInterface;
    
    /**
     * Returns the duration of the {@see API\SpanInterface} in nanoseconds.
     * If still active, returns `now() - start`.
     */
    public function getDuration() : int;
    
    /**
     * @see API\SpanKind
     */
    public function getKind() : int;
    
    /**
     * Returns the value of the attribute with the provided *key*.
     * Returns `null` if there are no attributes set, or no attribute with that key exists.
     *
     * @return mixed
     */
    public function getAttribute(string $key);

}