IssueTracker

The Javascript API uses the AutocompleteSessionToken wrapper class, but there is no public interface to get the raw string for use continuing the session server-side.

# Describe your issue

The Places (New) autocomplete session pricing model supports a "checkout and delivery" scenario where autocomplete using Places (New) followed by a call to the Address Validation API is charged as a single session under the "Address Validation Preferred" SKU.

This makes it possible to take autocomplete input on the client-side, and perform final validation on the server-side using the Address Validation API, enforcing much stronger protections than trusting the client-side. For example, shipping costs may be calculated server-side using this data, without needing to worry about the client submitting modified parameters.

This hybrid client/server session model is documented as working as long as the session token is shared and the API keys belong to the same GCP project.

However, the current Maps Javascript API doesn't seem to make the raw session token string underlying AutocompleteSessionToken accessible.

As such one has to either not use the Maps Javascript API and re-implement the client-side calls to the Maps web service APIs using raw fetch() requests, or extract the raw session token from the AutocompleteSessionToken object by inspecting the property names.

# Please report the version of Google Maps API
3.59.5

# What steps will reproduce the problem? Please also provide a code sample which demonstrates your issue (e.g. via jsfiddle.net, or jsbin.com)
1. Implement autocomplete client-side using Places (New) AutocompleteSuggestion.fetchAutocompleteSuggestions requests with a AutocompleteSessionToken sessionToken
2. Implement address validation using the Address Validation API web service
3.Try to combine the two in one session by somehow getting the session token from step 1.