Add missing imports (#1191)

### Motivation: CI was failing on 6.1+ because of missing explicit imports. ### Modifications: Added missing imports based on the error emitted on 6.1. ### Result: Makes 6.1 CI compile.

Author: czechboy0

IntegrationTests/tests_01_cluster/it_Clustered_swim_suspension_reachability/main.swift

@@ -13,6 +13,8 @@
 //===----------------------------------------------------------------------===//
 
 import DistributedCluster
+import Logging
+import SWIM
 
 print("Getting args")
 

MultiNodeTests/DistributedActorsMultiNodeTests/MultiNode+ClusterSingletonTests.swift

@@ -13,6 +13,7 @@
 //===----------------------------------------------------------------------===//
 
 import DistributedCluster
+import Logging
 import MultiNodeTestKit
 
 public final class MultiNodeClusterSingletonTests: MultiNodeTestSuite {

MultiNodeTests/DistributedActorsMultiNodeTests/MultiNode+MultiNodeConductorTests.swift

@@ -13,6 +13,7 @@
 //===----------------------------------------------------------------------===//
 
 import DistributedCluster
+import Logging
 import MultiNodeTestKit
 
 /// Tests of the ``MultiNodeTestConductor`` itself.

MultiNodeTests/DistributedActorsMultiNodeTests/MultiNode+ReceptionistTests.swift

@@ -13,6 +13,7 @@
 //===----------------------------------------------------------------------===//
 
 import DistributedCluster
+import Logging
 import MultiNodeTestKit
 
 public final class MultiNodeReceptionistTests: MultiNodeTestSuite {

Package.swift

@@ -36,6 +36,7 @@ var targets: [PackageDescription.Target] = [
  .product(name: "Atomics", package: "swift-atomics"),
  .product(name: "SWIM", package: "swift-cluster-membership"),
  .product(name: "NIO", package: "swift-nio"),
+ .product(name: "NIOPosix", package: "swift-nio"),
  .product(name: "NIOFoundationCompat", package: "swift-nio"),
  .product(name: "NIOSSL", package: "swift-nio-ssl"),
  .product(name: "NIOExtras", package: "swift-nio-extras"),

Sources/DistributedActorsTestKit/Cluster/ClusteredActorSystemsXCTestCase.swift

@@ -14,6 +14,8 @@
 
 import DistributedActorsConcurrencyHelpers
 import Foundation
+import Logging
+import SWIM
 import XCTest
 
 @testable import DistributedCluster

Sources/DistributedCluster/ActorContext.swift

@@ -12,6 +12,7 @@
 //
 //===----------------------------------------------------------------------===//
 
+import Foundation
 import Logging
 
 /// The `_ActorContext` exposes an actors details and capabilities, such as names and timers.

Sources/DistributedCluster/ActorShell+Children.swift

@@ -13,6 +13,7 @@
 //===----------------------------------------------------------------------===//
 
 import Dispatch
+import Logging
 import NIO
 
 internal enum Child {

Sources/DistributedCluster/Behaviors.swift

@@ -12,6 +12,9 @@
 //
 //===----------------------------------------------------------------------===//
 
+import NIOCore
+import NIOPosix
+
 /// A `_Behavior` is what executes when an `Actor` handles messages.
 ///
 /// The most important behavior is `_Behavior.receive` since it allows handling incoming messages with a simple block.

Sources/DistributedCluster/Cluster/ClusterShell.swift

@@ -12,6 +12,7 @@
 //
 //===----------------------------------------------------------------------===//
 
+import CoreMetrics
 import DistributedActorsConcurrencyHelpers
 import Logging
 import NIO