How to use the @opentelemetry/core.randomSpanId function in @opentelemetry/core

startSpan(name: string, options: types.SpanOptions = {}): types.Span {
    const parentContext = this._getParentSpanContext(options.parent);
    // make sampling decision
    const samplingDecision = this._sampler.shouldSample(parentContext);
    const spanId = randomSpanId();
    let traceId;
    let traceState;
    if (!parentContext || !isValid(parentContext)) {
      // New root span.
      traceId = randomTraceId();
    } else {
      // New child span.
      traceId = parentContext.traceId;
      traceState = parentContext.traceState;
    }
    const traceFlags = samplingDecision
      ? TraceFlags.SAMPLED
      : TraceFlags.UNSAMPLED;
    const spanContext = { traceId, spanId, traceFlags, traceState };
    const recordEvents = options.isRecording || false;
    if (!recordEvents && !samplingDecision) {