can manually refresh when updateInterval==0

pubspec.lock

@@ -28,7 +28,7 @@ packages:
       name: async
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "2.8.1"
+    version: "2.8.2"
   boolean_selector:
     dependency: transitive
     description:
@@ -42,7 +42,7 @@ packages:
       name: characters
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "1.1.0"
+    version: "1.2.0"
   charcode:
     dependency: transitive
     description:
@@ -264,7 +264,7 @@ packages:
       name: matcher
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "0.12.10"
+    version: "0.12.11"
   meta:
     dependency: transitive
     description:
@@ -363,6 +363,13 @@ packages:
       url: "https://pub.dartlang.org"
     source: hosted
     version: "6.0.1"
+  pull_to_refresh:
+    dependency: "direct main"
+    description:
+      name: pull_to_refresh
+      url: "https://pub.dartlang.org"
+    source: hosted
+    version: "2.0.0"
   r_upgrade:
     dependency: "direct main"
     description:
@@ -423,7 +430,7 @@ packages:
       name: test_api
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "0.4.2"
+    version: "0.4.3"
   typed_data:
     dependency: transitive
     description:
@@ -493,7 +500,7 @@ packages:
       name: vector_math
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "2.1.0"
+    version: "2.1.1"
   win32:
     dependency: transitive
     description: