Panic during network loss

[jrick]

Upon restarting my router for an upgrade I got this panic:

panic: runtime error: invalid memory address or nil pointer dereference       
        panic: runtime error: invalid memory address or nil pointer dereference
[signal SIGSEGV: segmentation violation code=0x1 addr=0x0 pc=0x80c70b]

goroutine 36 [running]:
github.com/companyzero/zkc/session.(*KX).Close(...)
        /home/jrick/src/zkc/session/kx.go:124
main.(*ZKC).handleRPC.func1(0xc000b911a0, 0xc000ba7030, 0xc0000e01c0, 0xc001e89808)
        /home/jrick/src/zkc/zkclient/zkclient.go:1201 +0x8b
panic(0x865ca0, 0xbb5430)
        /home/jrick/src/go/src/runtime/panic.go:975 +0x3e9
github.com/companyzero/zkc/session.(*KX).Read(...)
        /home/jrick/src/zkc/session/kx.go:414
main.(*ZKC).handleRPC(0xc0000e01c0)
        /home/jrick/src/zkc/zkclient/zkclient.go:1289 +0x172
created by main.(*ZKC).goOnlineAndPrint
        /home/jrick/src/zkc/zkclient/zkclient.go:1005 +0x1fb

This is with a slightly earlier version of my #162 PR; sorry if the line numbers don't match up exactly. I don't think the PR is necessarily related.

It seems that z.kx was nil and that it panicked twice. Once, while reading, and a second time from a deferred KX.Close call.

[jrick]

This seems definitely related to my patch. Been running with and without it, and evidence only points to the version built with my patch crashing in this manner.