Adding support for TCP port forwarding

[dmitry-zaitsev]

As requested in issue #1

Usage (Kotlin):

dadb.tcpForward(
    hostPort = 7001,
    targetPort = 7001
).use {
    // Do operations that depend on port forwarding
}

[mfilenko]

Thanks a lot for taking care of this, Dima! 👏

[Leland-Takamine]

Let's add documentation for this api in the Readme as well

[Leland-Takamine]

Should the forwarding be able to automatically recover from IO errors on either end?

[dmitry-zaitsev]

@Leland-Takamine the part which can throw an exception is a forward method. In case of an exception, we shouldn't just retry as there is no guarantee that the receiver is idempotent and should instead surface the error to the user.

[Leland-Takamine]

This implementation seems more straightforward: TCPForwardServer

Are we handling cases that the above implementation doesn't handle?

[dmitry-zaitsev]

@Leland-Takamine TCPForwardServer is nice (and a source of inspiration), but it misses some points:

• It blocks the thread once started. Meaning we have to handle the serverThread ourselves.
• Assumes that the server will keep running forever (it won't). When the server is stopped, we need to wait for resources to be closed before it can be started up again (otherwise ports might be unavailable) which is not instantaneous.

[Leland-Takamine]

Got it - looks good to me!