beiping96

I try to build an IMAP email client, and it has many email accounts. When I use the `pprof` for debugging my codes, I found in some cases, the `UidFetch`...

``` bash panic: runtime error: index out of range [1] with length 1 goroutine 1644487 [running]: github.com/emersion/go-imap/client.(*Client).handleUnilateral.func1(0xce80e0, 0xc001782de0, 0xce8020, 0xc00018c590) /home/pp/go/pkg/mod/github.com/emersion/[email protected]/client/client.go:437 +0xcca github.com/emersion/go-imap/responses.HandlerFunc.Handle(0xc00898d790, 0xce80e0, 0xc001782de0, 0xce8001, 0xc00018c590) /home/pp/go/pkg/mod/github.com/emersion/[email protected]/responses/responses.go:27 +0x3a github.com/emersion/go-imap/client.(*Client).handle(0xc0002af2c0,...