Remove mutex as the locking is now done in the library.

main.go

@@ -18,7 +18,6 @@ import (
 	osUser "os/user"
 	"runtime"
 	"strings"
-	"sync"
 	"time"
 
 	"github.com/ProtonMail/gopenpgp/v2/crypto" // MIT License
@@ -34,11 +33,8 @@ type configuration struct {
 	alias    string
 }
 
-var mutex sync.Mutex
-
 func closeAndExit(client *xmpp.Client, cancel context.CancelFunc, err error) {
 	cancel()
-	mutex.Lock()
 	client.Close()
 	if err != nil {
 		log.Fatal(err)

stanzahandling.go

@@ -53,17 +53,14 @@ func rcvStanzas(client *xmpp.Client, iqc chan xmpp.IQ, msgc chan xmpp.Chat, ctx
 		case <-ctx.Done():
 			return
 		default:
-			mutex.Lock()
 			go func() {
 				received, err = client.Recv()
 				r <- received
 			}()
 			select {
 			case <-ctx.Done():
-				mutex.Unlock()
 				return
 			case <-r:
-				mutex.Unlock()
 			}
 		}
 		// Don't print errors if the program is getting shut down,