OptionalminThe zoom level from which the labels of markers are shown, with one decimal place, above 0 and
up to 22 (MAX_ZOOM), e.g. 12.5. Without it, at every zoom level.
OptionaloverlapLabels of markers that would overlap other labels: "show" them all, also on top of each other, or "hide" them (their symbols stay).
How the labels of markers are shown: whether they may overlap, and from which zoom level.