private void addRowSegment(RowSegment<E> rowSegment) {
		int row = rowSegment.getRow();
		RowSegmentList<E> edgeRow =
			rowSegmentMap.computeIfAbsent(row, k -> new RowSegmentList<E>(k));
		edgeRow.addSegment(rowSegment);
	}
Finds the column segment object for the given edge and start point.
@param edge the edge for which to find its column segment object
@param gridPoint the start point for the desired segment object
@return the column segment object for the given edge and start point.
Ghidra/Features/FunctionGraph/src/main/java/ghidra/app/plugin/core/functiongraph/graph/layout/flowchart/EdgeSegmentMap.java