IncrementalNewlineDecoder from pyio

Lib/io.py

@@ -121,3 +121,10 @@ except ImportError:
     pass
 else:
     RawIOBase.register(_WindowsConsoleIO)
+
+
+# XXX: RUSTPYTHON; borrow IncrementalNewlineDecoder from _pyio
+try:
+    from _pyio import IncrementalNewlineDecoder
+except ImportError:
+    pass

Lib/test/test_io.py

@@ -3895,11 +3895,6 @@ class CTextIOWrapperTest(TextIOWrapperTest):
     def test_reconfigure_write(self):
         super().test_reconfigure_write()
 
-    # TODO: RUSTPYTHON
-    @unittest.expectedFailure
-    def test_reconfigure_write_non_seekable(self):
-        super().test_reconfigure_write_non_seekable()
-
     # TODO: RUSTPYTHON
     @unittest.expectedFailure
     def test_reconfigure_defaults(self):