batchReady(currTime) {
    return this.spans.length >= this.batchSize || currTime - this.time >= this.queueInterval
  }
The Infinite Tracing trace observer will treat spans that are more than 10 seconds apart as not belonging to the same group.
 It is therefore recommended that the agent perform a RecordSpanBatch request when either a target maximum batch size is reached or 5 seconds have elapsed since the creation of a batch (giving precedence to whichever of these events takes place first).
 Otherwise, delayed recording of spans will lead to their being discarded.

@param {number} currTime timestamp in milliseconds
@returns {boolean} if a batch can we sent