Expose RpcServer::setMaxThreads in BinderRpc Rust API.

Bug: 332776171
Test: manual
Change-Id: I6b284d93c35230f99350c77dff2b7bb7ad79dd87
diff --git a/libs/binder/libbinder_rpc_unstable.cpp b/libs/binder/libbinder_rpc_unstable.cpp
index cb44c58..21537fc 100644
--- a/libs/binder/libbinder_rpc_unstable.cpp
+++ b/libs/binder/libbinder_rpc_unstable.cpp
@@ -167,6 +167,10 @@
     server->setSupportedFileDescriptorTransportModes(modevec);
 }
 
+void ARpcServer_setMaxThreads(ARpcServer* handle, size_t threads) {
+    handleToStrongPointer<RpcServer>(handle)->setMaxThreads(threads);
+}
+
 void ARpcServer_start(ARpcServer* handle) {
     handleToStrongPointer<RpcServer>(handle)->start();
 }