Mark types explicitly non sendable (#2290)

Sources/NIOCore/FileRegion.swift

@@ -82,6 +82,11 @@ public struct FileRegion {
     }
 }
 
+#if swift(>=5.6)
+@available(*, unavailable)
+extension FileRegion: Sendable {}
+#endif
+
 extension FileRegion {
     /// Create a new `FileRegion` forming a complete file.
     ///

Sources/NIOCore/IOData.swift

@@ -30,6 +30,11 @@ public enum IOData {
 /// `IOData` objects are comparable just like the values they wrap.
 extension IOData: Equatable {}
 
+#if swift(>=5.6)
+@available(*, unavailable)
+extension IOData: Sendable {}
+#endif
+
 /// `IOData` provide a number of readable bytes.
 extension IOData {
     /// Returns the number of readable bytes in this `IOData`.

Sources/NIOCore/NIOAny.swift

@@ -257,6 +257,11 @@ public struct NIOAny {
     }
 }
 
+#if swift(>=5.6)
+@available(*, unavailable)
+extension NIOAny: Sendable {}
+#endif
+
 extension NIOAny: CustomStringConvertible {
     public var description: String {
         return "NIOAny { \(self.asAny()) }"