A ~hack~ patch to teach net/textproto how to ignore `050`

net-textproto-ignore-050.patch

diff --git a/src/net/textproto/reader.go b/src/net/textproto/reader.go
index a00fd2395f..9f82186c62 100644
--- a/src/net/textproto/reader.go
+++ b/src/net/textproto/reader.go
@@ -10,6 +10,7 @@ import (
        "fmt"
        "io"
        "io/ioutil"
+       "log"
        "strconv"
        "strings"
        "sync"
@@ -190,11 +191,20 @@ func (r *Reader) skipSpace() int {
 }

 func (r *Reader) readCodeLine(expectCode int) (code int, continued bool, message string, err error) {
-       line, err := r.ReadLine()
-       if err != nil {
-               return
+       for {
+               line, err := r.ReadLine()
+               if err != nil {
+                       return 0, false, "", err
+               }
+               code, continued, message, err = parseCodeLine(line, expectCode)
+               if err != nil {
+                       if strings.HasPrefix(err.Error(), "invalid response code: 050") {
+                               log.Println("[+] Skipping:", err.Error())
+                               continue
+                       }
+               }
+               return code, continued, message, err
        }
-       return parseCodeLine(line, expectCode)
 }

 func parseCodeLine(line string, expectCode int) (code int, continued bool, message string, err error) {