Make TCP buffers configurable

[magiconair]

This patch adds methods to configure the receive and transmit
buffers of the underlying TCP connection.

[magiconair]

We ran into this today and hard-coded the changes. Need to see whether this approach works as well or whether we need to call SetReadBuffer/SetWriteBuffer after Dial but before the uacp handshake for this to work.

[kung-foo]

I wonder if we should just promote the underlying conn:

type Conn struct {
        net.Conn
	id  uint32
	ack *Acknowledge
}

or if we can assume it is always TCP:

type Conn struct {
        net.TCPConn
	id  uint32
	ack *Acknowledge
}

[magiconair]

net.Conn does not have the SetRead/WriteBuffer methods. We would have to type check twice.

Unless we support Websockets it will be TCP and even then.

[kung-foo]

Maybe this? 6f756f3

[magiconair]

This looks good. Let me test that.

[kung-foo]

note: I didn't understand this bit right here: 6f756f3#diff-e06a25cad06b1ecd848e968ae7d9984eL293-R270

There's some bad naming, and aliasing going on. And I don't think there's anything that tests that path.

[magiconair]

This is for the reverse handshake but we don't have any tests for that I think.