Add SendIQ to StreamClient and Sender

This makes it possible to use SendIQ from PostConnect and route handlers.

stream_manager.go

@@ -1,6 +1,7 @@
 package xmpp
 
 import (
+	"context"
 	"errors"
 	"sync"
 	"time"
@@ -26,6 +27,7 @@ type StreamClient interface {
 	Connect() error
 	Resume(state SMState) error
 	Send(packet stanza.Packet) error
+	SendIQ(ctx context.Context, iq stanza.IQ) (chan stanza.IQ, error)
 	SendRaw(packet string) error
 	Disconnect()
 	SetHandler(handler EventHandler)
@@ -35,6 +37,7 @@ type StreamClient interface {
 // It is mostly use in callback to pass a limited subset of the stream client interface
 type Sender interface {
 	Send(packet stanza.Packet) error
+	SendIQ(ctx context.Context, iq stanza.IQ) (chan stanza.IQ, error)
 	SendRaw(packet string) error
 }