Cumulative END time (ms) of each segment; length = segments.count, monotonic non-decreasing.
hasUnknownFeedrate
hasUnknownFeedrate:boolean
True if any moving segment had an unknown feedrate (contributed 0). The estimate is then a lower
bound / approximate — a consumer should disclose it (and prefer the slicer estimate when present).
Cumulative END time (ms) of each segment; length =
segments.count, monotonic non-decreasing.