socket.io transport error

[balaphp]

command i have used: websocket-bench -a 100000 -c 10000 -w 4 {url}
/usr/local/lib/node_modules/websocket-bench/node_modules/socket.io-client/lib/socket.js:281
self.transport.onClose();
^
TypeError: Cannot call method 'onClose' of null
at null._onTimeout (/usr/local/lib/node_modules/websocket-bench/node_modules/socket.io-client/lib/socket.js:281:22)
at Timer.listOnTimeout as ontimeout

/usr/local/lib/node_modules/websocket-bench/node_modules/socket.io-client/lib/socket.js:281
self.transport.onClose();
^
TypeError: Cannot call method 'onClose' of null
at null._onTimeout (/usr/local/lib/node_modules/websocket-bench/node_modules/socket.io-client/lib/socket.js:281:22)
at Timer.listOnTimeout as ontimeout

[balaphp]

i am getting same error for websocket-bench -a 25000-c 1000 -w 4 {url}

[thanhson1085]

+1

[hequanb]

hello, what's situation in using argument -w <n> ,