it fails with this errors sometimes, not reliably on any particular change but just after a little while:
convox | sync add error: io: read/write on closed pipe
panic: send on closed channel
goroutine 23995 [running]:
github.com/convox/rack/pkg/start.Options2.handleAdds.func1(0xc0012c99e0, 0xc000192300, 0x7, 0x101, 0x0, 0x0, 0x5ac60e0, 0xc0002454a0, 0x0, 0x0, ...)
/ext-go/1/src/github.com/convox/rack/pkg/start/gen2.go:242 +0xb1
created by github.com/convox/rack/pkg/start.Options2.handleAdds
/ext-go/1/src/github.com/convox/rack/pkg/start/gen2.go:241 +0x2c0
$ convox version
client: 20190130162938
server: 20190130162938 (rack.convox)