v3.4.3: Updated the write getter to return the socket as Writable (#62)

#### What is this change?

Instead of trying to wrap the tty `ReadStream` with `Writable` and sync
the states, we can just return the `ReadStream` as a `Writable` in the
`write` getter. In this case, when the fd is closed or destroyed, the
`writable` will also be `closed`.

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Co-authored-by: Jacky Zhao <j.zhao2k19@gmail.com>