Ignore ERROR_MORE_DATA as a non-fatal error when returned by

GetOverlappedResult for a synchronous read.

Author: chriskohlhoff

asio/include/asio/detail/impl/win_iocp_handle_service.ipp

@@ -439,14 +439,17 @@ size_t win_iocp_handle_service::do_read(
   if (!ok)
   {
     DWORD last_error = ::GetLastError();
-    if (last_error == ERROR_HANDLE_EOF)
+    if (last_error != ERROR_MORE_DATA)
     {
-      ec = asio::error::eof;
-    }
-    else
-    {
-      ec = asio::error_code(last_error,
-          asio::error::get_system_category());
+      if (last_error == ERROR_HANDLE_EOF)
+      {
+        ec = asio::error::eof;
+      }
+      else
+      {
+        ec = asio::error_code(last_error,
+            asio::error::get_system_category());
+      }
     }
     return 0;
   }