additionalParameters

Optional vendor-specific extra parameters to attach to outgoing directions requests (initial route, reroute, alternative continuation) and route refreshes via the ev_additional_parameters query parameter.

The map is serialized as key1:value1,key2:value2.

Constraints:

• Keys and values must not contain : or , — these are used as separators and are not escaped.

• Keys and values must be URL-safe; no further encoding is applied.

• Iteration order of the map defines serialization order; use a map with stable iteration (e.g. LinkedHashMap) if order matters.

Returning null or an empty map omits the parameter entirely.