Restore missing OkHttp3 Additions in okhttp-android and okhttp-jvm

[Copilot]

The OkHttp3 Additions (hand-written helper/extension APIs) were dropped when the okhttp binding was split into okhttp-android (Square.OkHttp3.Android) and okhttp-jvm (Square.OkHttp3.JVM) for 5.x. Consumers lost APIs such as ICall.ExecuteAsync():

Square.OkHttp3.ICall call;
await call.ExecuteAsync(); // CallExtensions was no longer available

Changes

• Restored Additions into both new binding projects (each .csproj already globs Additions/*.cs):
  • Call.cs — CallExtensions.ExecuteAsync(this ICall) and Enqueue(this ICall, Action<ICall,Response>, Action<ICall,IOException>) + internal ICallback adapter
  • Dispatcher.cs — Dispatcher.SetIdleCallback(IRunnable)
  • OkHttpClient.Builder.cs — Func-based overloads for AddInterceptor, AddNetworkInterceptor, Authenticator, ProxyAuthenticator, Dns, HostnameVerifier + delegate adapters
  • ResponseBody.cs — BytesAsync(), StringAsync()
• Backward compat: added a TypeForwardedTo for the new Square.OkHttp3.CallExtensions type in the okhttp shim. Other additions are members of already-forwarded types and need no entry.
• PublicAPI: added the 12 new members to PublicAPI.Unshipped.txt for both projects, in generator-matching sorted positions.

Notes

• Mirrored into both okhttp-android and okhttp-jvm so .Android and .JVM consumers reach parity with the pre-split okhttp package.
• IAuthenticator.Authenticate now has a nullable Route? parameter in 5.x; the restored Func<Route, Response, Request> signature is preserved as previously shipped, yielding a benign (non-fatal) nullability warning rather than a behavior/API change.

[Copilot]

Pull request overview

This PR restores previously shipped OkHttp3 “Additions” (hand-written helper APIs) that were lost when the okhttp binding split into okhttp-android (Square.OkHttp3.Android) and okhttp-jvm (Square.OkHttp3.JVM) for 5.x, and adds a type-forward in the okhttp shim to preserve source/binary compatibility for the newly reintroduced CallExtensions type.

Changes:

• Reintroduces helper APIs into both okhttp-android and okhttp-jvm (async helpers, delegate-based builder overloads, dispatcher helper, call extensions).
• Adds TypeForwardedTo for Square.OkHttp3.CallExtensions in the okhttp shim assembly.
• Updates PublicAPI.Unshipped.txt for both bindings to include the restored public surface area.

Reviewed changes

Copilot reviewed 11 out of 11 changed files in this pull request and generated 8 comments.

Show a summary per file

File	Description
source/com.squareup.okhttp3/okhttp/Additions/TypeForwards.cs	Adds a type-forward for the newly restored Square.OkHttp3.CallExtensions type for backward compatibility.
source/com.squareup.okhttp3/okhttp-android/Additions/Call.cs	Restores CallExtensions helpers (ExecuteAsync, delegate-based Enqueue).
source/com.squareup.okhttp3/okhttp-android/Additions/Dispatcher.cs	Adds Dispatcher.SetIdleCallback(IRunnable) helper.
source/com.squareup.okhttp3/okhttp-android/Additions/OkHttpClient.Builder.cs	Adds Func-based overloads for interceptors/authenticators/DNS/hostname verification via adapter implementations.
source/com.squareup.okhttp3/okhttp-android/Additions/ResponseBody.cs	Adds async convenience methods for ResponseBody (BytesAsync, StringAsync).
source/com.squareup.okhttp3/okhttp-android/PublicAPI/PublicAPI.Unshipped.txt	Declares the new public members/types for the Android binding in the API baseline.
source/com.squareup.okhttp3/okhttp-jvm/Additions/Call.cs	Restores CallExtensions helpers (ExecuteAsync, delegate-based Enqueue).
source/com.squareup.okhttp3/okhttp-jvm/Additions/Dispatcher.cs	Adds Dispatcher.SetIdleCallback(IRunnable) helper.
source/com.squareup.okhttp3/okhttp-jvm/Additions/OkHttpClient.Builder.cs	Adds Func-based overloads for interceptors/authenticators/DNS/hostname verification via adapter implementations.
source/com.squareup.okhttp3/okhttp-jvm/Additions/ResponseBody.cs	Adds async convenience methods for ResponseBody (BytesAsync, StringAsync).
source/com.squareup.okhttp3/okhttp-jvm/PublicAPI/PublicAPI.Unshipped.txt	Declares the new public members/types for the JVM binding in the API baseline.