diff --git a/lib/resty/websocket/client.lua b/lib/resty/websocket/client.lua
index 41e41bb..4c3d491 100644
--- a/lib/resty/websocket/client.lua
+++ b/lib/resty/websocket/client.lua
@@ -230,7 +230,7 @@ function _M.recv_frame(self)
 end
 
 
-local function send_frame(self, fin, opcode, payload, max_payload_len)
+local function send_frame(self, fin, opcode, payload)
     if self.fatal then
         return nil, "fatal error already happened"
     end
diff --git a/lib/resty/websocket/protocol.lua b/lib/resty/websocket/protocol.lua
index 37050de..b2f19ec 100644
--- a/lib/resty/websocket/protocol.lua
+++ b/lib/resty/websocket/protocol.lua
@@ -12,7 +12,8 @@ local bor = bit.bor
 local bxor = bit.bxor
 local lshift = bit.lshift
 local rshift = bit.rshift
-local tohex = bit.tohex
+--local tohex = bit.tohex
+local tostring = tostring
 local concat = table.concat
 local str_char = string.char
 local rand = math.random