net.mtu = 256
function net.sendstring(addr,port,msg) -- for sending lots of data
 net.send(addr,port,math.ceil(msg:len()/net.mtu))
 for i = 1, #msg, net.mtu do
  net.send(addr,port,msg:sub(i,(i+net.mtu)-1))
  coroutine.yield()
  coroutine.yield()
 end
end
function net.recvstring(addr,port)
 local fr,po,msg = ""
 repeat
  _,fr,po,msg = event.pull("net_msg")
 until fr == addr and po == port
 local ml,s = tonumber(msg), ""
 for i = 1, ml do
  _,fr,po,msg = event.pull("net_msg")
  if fr == addr and po == port then
   s=s..tostring(msg)
  end
 end
 return s
end