telemetry: Initialize telemetry asynchronously (#35898)

close pingcap/tidb#35897

session/session.go

@@ -2879,8 +2879,10 @@ func BootstrapSession(store kv.Storage) (*domain.Domain, error) {
 	if dom.GetEtcdClient() != nil {
 		// We only want telemetry data in production-like clusters. When TiDB is deployed over other engines,
 		// for example, unistore engine (used for local tests), we just skip it. Its etcd client is nil.
-		dom.TelemetryReportLoop(ses[5])
-		dom.TelemetryRotateSubWindowLoop(ses[5])
+		go func() {
+			dom.TelemetryReportLoop(ses[5])
+			dom.TelemetryRotateSubWindowLoop(ses[5])
+		}()
 	}
 
 	// A sub context for update table stats, and other contexts for concurrent stats loading.