Error suppressed - connection refused

[Jarvie8176]

I basically tried to test the library with no thrift server running. constructor option is

{
    host: "127.0.0.1",
    port: 8000,
    max_connections: 1,
    min_connections: 0,
    idle_timeout: 1 * 1000,
    ssl: false
}

then i got an error of

"TypeError: cb is not a function"
at /node_modules/node-thrift-pool/index.js:143:18

but i'd expect the same error as in debug message:

  thrift-pool in error callback +0ms
  thrift-pool Connection acquired +2ms
  thrift-pool { err: { Error: connect ECONNREFUSED 127.0.0.1:8000 at Object.exports._errnoException (util.js:1007:11) at exports._exceptionWithHostPort (util.js:1030:20) at TCPConnectWrap.afterConnect [as oncomplete] (net.js:1080:14) code: 'ECONNREFUSED', errno: 'ECONNREFUSED', syscall: 'connect', address: '127.0.0.1', port: 8000 } } +1ms
  thrift-pool in close callback +8ms

is this error message expected?