public PlaceAutocompleteRequest sessionToken(SessionToken sessionToken) {
    return param("sessiontoken", sessionToken);
  }
Sets the SessionToken for this request. Using session token makes sure the autocomplete is
priced per session, instead of per keystroke.

@param sessionToken Session Token is the session identifier.
@return Returns this {@code PlaceAutocompleteRequest} for call chaining.
src/main/java/com/google/maps/PlaceAutocompleteRequest.java