fix: do not block identify on SSE client shutdown completion

Author: cwaldren-ld

libs/client-sdk/src/client_impl.cpp

@@ -149,14 +149,11 @@ std::future<bool> ClientImpl::IdentifyAsync(Context context) {
 }
 
 void ClientImpl::RestartDataSource() {
-    auto start_op = [this]() {
-        data_source_ = data_source_factory_();
-        data_source_->Start();
-    };
-    if (!data_source_) {
-        return start_op();
+    if (data_source_) {
+        data_source_->ShutdownAsync(nullptr);
     }
-    data_source_->ShutdownAsync(start_op);
+    data_source_ = data_source_factory_();
+    data_source_->Start();
 }
 
 std::future<bool> ClientImpl::StartAsyncInternal(
@@ -170,7 +167,7 @@ std::future<bool> ClientImpl::StartAsyncInternal(
             if (auto const state = status.State(); IsInitialized(state)) {
                 init_promise->set_value(result(status.State()));
                 return true; /* delete this change listener since the desired
-                                state was reached */
+                        state was reached */
             }
             return false; /* keep the change listener */
         });