OptionalxOptionalyOptionalxModern Vega-Lite dodge channel — when paired with a categorical
field, Vega-Lite places bars of each subcategory side-by-side
within the same x slot. The adapter inspects this to classify a
bar mark as DODGED rather than STACKED.
OptionalyVertical counterpart of xOffset.
OptionalcolorOptionalfillOptionalrowOptionalcolumn
The encoding channels that the adapter inspects when mapping a Vega-Lite spec to a MAIDR trace.