The name of the bin, which must contain a Map value.
The map key.
OptionalreturnType: maps.returnTypeThe return type indicating what data of the selected item(s) to return.
Operation that can be passed to the Client#operate command.
Instead of passing returnType, you can also use
~MapOperation#andReturn|MapOperation#andReturn to
select what data to return.
Retrieves a single item identified by key from the map.