fn enforce_file_num<T: Item>(files: &[T], max_file_num: usize) -> Vec<T>Expand description
Merges consecutive files so that file num does not exceed max_file_num, and chooses
the solution with minimum overhead according to files sizes to be merged.
enforce_file_num only merges consecutive files so that it won’t create overlapping outputs.
runs must be sorted according to time ranges.