Number of points dropped from the front by the maxWidth sliding window.
How far a maxWidth trim moves the cursor along the trace's column axis,
so a reader keeps the point they were on.
trimmed wherever columns index the data points in arrival order, which
is most traces. Zero where they do not: a horizontal box navigates its
sections along the column axis, and a scatter's columns are its sorted
unique x values, which a trim does not shift by any fixed amount.
True when the point was merged into a nested group layer (e.g. multiline),
where row is the series index. For flat layers row/col are announce
coordinates whose meaning depends on the trace type (e.g. candlestick
rows are OHLC sections).
Location of a newly appended data point, expressed in trace coordinates (
row= group/series index,col= point index within the group).