diff --git a/src/crystal/system/win32/iocp.cr b/src/crystal/system/win32/iocp.cr
index 278c6f564d64..ac218290f789 100644
--- a/src/crystal/system/win32/iocp.cr
+++ b/src/crystal/system/win32/iocp.cr
@@ -130,25 +130,6 @@ module Crystal::IOCP
         end
       end
     end
-
-    private def try_cancel : Bool
-      # Microsoft documentation:
-      # The application must not free or reuse the OVERLAPPED structure
-      # associated with the canceled I/O operations until they have completed
-      # (this does not apply to asynchronous operations that finished
-      # synchronously, as nothing would be queued to the IOCP)
-      ret = LibC.CancelIoEx(@handle, self)
-      if ret.zero?
-        case error = WinError.value
-        when .error_not_found?
-          # Operation has already completed, do nothing
-          return false
-        else
-          raise RuntimeError.from_os_error("CancelIoEx", os_error: error)
-        end
-      end
-      true
-    end
   end
 
   class IOOverlappedOperation < OverlappedOperation
@@ -168,6 +149,25 @@ module Crystal::IOCP
 
       bytes
     end
+
+    private def try_cancel : Bool
+      # Microsoft documentation:
+      # The application must not free or reuse the OVERLAPPED structure
+      # associated with the canceled I/O operations until they have completed
+      # (this does not apply to asynchronous operations that finished
+      # synchronously, as nothing would be queued to the IOCP)
+      ret = LibC.CancelIoEx(@handle, self)
+      if ret.zero?
+        case error = WinError.value
+        when .error_not_found?
+          # Operation has already completed, do nothing
+          return false
+        else
+          raise RuntimeError.from_os_error("CancelIoEx", os_error: error)
+        end
+      end
+      true
+    end
   end
 
   class WSAOverlappedOperation < OverlappedOperation
@@ -188,6 +188,25 @@ module Crystal::IOCP
 
       bytes
     end
+
+    private def try_cancel : Bool
+      # Microsoft documentation:
+      # The application must not free or reuse the OVERLAPPED structure
+      # associated with the canceled I/O operations until they have completed
+      # (this does not apply to asynchronous operations that finished
+      # synchronously, as nothing would be queued to the IOCP)
+      ret = LibC.CancelIoEx(Pointer(Void).new(@handle), self)
+      if ret.zero?
+        case error = WinError.value
+        when .error_not_found?
+          # Operation has already completed, do nothing
+          return false
+        else
+          raise RuntimeError.from_os_error("CancelIoEx", os_error: error)
+        end
+      end
+      true
+    end
   end
 
   def self.overlapped_operation(file_descriptor, method, timeout, *, offset = nil, writing = false, &)