feat: configurable TCPKeepAlive interval

adapter/outboundgroup/util.go

@@ -1,17 +1,5 @@
 package outboundgroup
 
-import (
-	"net"
-	"time"
-)
-
-func tcpKeepAlive(c net.Conn) {
-	if tcp, ok := c.(*net.TCPConn); ok {
-		_ = tcp.SetKeepAlive(true)
-		_ = tcp.SetKeepAlivePeriod(30 * time.Second)
-	}
-}
-
 type SelectAble interface {
 	Set(string) error
 	ForceSet(name string)