io. From ftp SSL draft:
  PORT w,x,y,z,a,b -------------------------------------------->
      <-------------------------------------------------------- 200
  STOR file --------------------------------------------------->
                                          socket()
                                          bind()
      <-------------------------------------------------------- 150
                   accept()  <----------  connect()
                   TLSneg()  <----------> TLSneg()
                   TLSwrite() ----------> TLSread()
                   TLSshutdown() -------> TLSshutdown()
                   close()    ----------> close()
      <-------------------------------------------------------- 226
Both accept and TLSnegotation should occur after 150 response has been sent to client. But I guess we can't blame you for supporting those servers