fix(datastore): Remove temporary fix to issue #395 (#967)

Author: HuiSF

packages/amplify_datastore/example/ios/unit_tests/DataStorePluginUnitTests.swift

@@ -334,21 +334,14 @@ class DataStorePluginUnitTests: XCTestCase {
                 // Return from the mock
                 completion(.emptyResult)
             }
-
-            let mockPublisher = PassthroughSubject<MutationEvent, DataStoreError>()
-            override func onObserve() throws -> AnyPublisher<MutationEvent, DataStoreError> {
-                mockPublisher.eraseToAnyPublisher()
-            }
         }
         let dataStoreBridge: MockDataStoreBridge = MockDataStoreBridge()
         pluginUnderTest = SwiftAmplifyDataStorePlugin(bridge: dataStoreBridge, flutterModelRegistration: flutterModelSchemaRegistration)
 
-        XCTAssertNil(pluginUnderTest.observeSubscription)
         pluginUnderTest.onClear(
             flutterResult: {(result) in
                 XCTAssertNil(result)
             })
-        XCTAssertNotNil(pluginUnderTest.observeSubscription)
     }
 
     func test_clear_failure_with_unknown_error() throws {

packages/amplify_datastore/ios/Classes/SwiftAmplifyDataStorePlugin.swift

@@ -28,7 +28,7 @@ public class SwiftAmplifyDataStorePlugin: NSObject, FlutterPlugin {
     private let dataStoreObserveEventStreamHandler: DataStoreObserveEventStreamHandler?
     private let dataStoreHubEventStreamHandler: DataStoreHubEventStreamHandler?
     private var channel: FlutterMethodChannel?
-    var observeSubscription: AnyCancellable?
+    private var observeSubscription: AnyCancellable?
 
     init(bridge: DataStoreBridge = DataStoreBridge(),
          flutterModelRegistration: FlutterModels = FlutterModels(),
@@ -341,10 +341,6 @@ public class SwiftAmplifyDataStorePlugin: NSObject, FlutterPlugin {
                         flutterResult: flutterResult)
                 case .success():
                     print("Successfully cleared the store")
-                    // iOS tears down the publisher after clear. Let's setup again.
-                    // See https://github.com/aws-amplify/amplify-flutter/issues/395
-                    self.observeSubscription = nil
-                    self.onSetUpObserve(flutterResult: flutterResult)
                     flutterResult(nil)
                 }
             }