Uses a simpler approach to trackign hoistables and only writes them e…

…ither during the preamble or when a boundary complets. The cost is that during the preamble flush there is an extra traversal of the segments that will write in the preamble. While this is not ideal for perf it does make the tracking significantly easier to follow and overall probalby strikes a better balance of practicality and maintainability over raw performance.