In your code, huge data passed to .write(huge) may be remained in the internal buffer.

```
[NEW PRE-FLUSH]

    else if ((self->pending_bytes_count + bytes_len) > self->chunk_size) {
        if (_textiowrapper_writeflush(self) < 0) {
            Py_DECREF(b);
            return NULL;
        }
        self->pending_bytes = b;
    }
(snip)
    self->pending_bytes_count += bytes_len;
    if (self->pending_bytes_count > self->chunk_size || needflush ||
        text_needflush) {
        if (_textiowrapper_writeflush(self) < 0)
            return NULL;
    }
```

In my opinion, when .write(huge) fails with MemoryError, TextIOWrapper must not keep the `huge` in the internal buffer.

See my PR-24592.