nextSegment(segmentSize) {
        this.segmentOffset = this.segmentOffset + this.segmentSize;
        this.segmentIndex = this.segmentIndex + 1;
        this.segmentSize = segmentSize;
        this.receivedBytes = 0;
        core.debug(`Downloading segment at offset ${this.segmentOffset} with length ${this.segmentSize}...`);
    }
Progress to the next segment. Only call this method when the previous segment
is complete.

@param segmentSize the length of the next segment