Fix closing hangs (#131)

A peer can make us wait forever when closing a connection.
This PR instead tries to be nice and wait for him, but kills the connection after a while

Author: Menduist

websock/session.nim

@@ -249,7 +249,10 @@ proc handleClose*(
   if ws.readyState != ReadyState.Closing:
     ws.readyState = ReadyState.Closing
     trace "Sending close", code = ord(code), reason
-    await ws.send(prepareCloseBody(code, reason), Opcode.Close)
+    try:
+      await ws.send(prepareCloseBody(code, reason), Opcode.Close).wait(5.seconds)
+    except CatchableError as exc:
+      trace "Failed to send Close opcode", err=exc.msg
 
     ws.readyState = ReadyState.Closed
 
@@ -502,18 +505,22 @@ proc close*(
   if ws.readyState != ReadyState.Open:
     return
 
-  try:
-    ws.readyState = ReadyState.Closing
+  proc gentleCloser(ws: WSSession, closeBody: seq[byte]) {.async.} =
     await ws.send(
-      prepareCloseBody(code, reason),
+      closeBody,
       opcode = Opcode.Close)
 
     # read frames until closed
     try:
       while ws.readyState != ReadyState.Closed:
         discard await ws.readFrame()
     except CatchableError as exc:
-      ws.readyState = ReadyState.Closed
-      await ws.stream.closeWait()
+      discard # most likely EOF
+  try:
+    ws.readyState = ReadyState.Closing
+    await gentleCloser(ws, prepareCloseBody(code, reason)).wait(10.seconds)
   except CatchableError as exc:
     trace "Exception closing", exc = exc.msg
+  finally:
+    await ws.stream.closeWait()
+    ws.readyState = ReadyState.Closed