dump了一下内存，发现大量这种对象……有些甚至能有上万的distance，中间全是next::WriteReq
这是一个WebSocket服务，几乎都是长连接保持状态，会有几百个活跃连接，用的是ws库
"dependencies": {
"bluebird": "^3.4.3",
"bufferutil": "^1.2.1",
"bunyan": "^1.8.1",
"co": "^4.6.0",
"co-redis": "^2.1.1",
"co-request": "^1.0.0",
"hiredis": "^0.5.0",
"json-stream": "^1.0.0",
"knex": "^0.11.10",
"moment": "^2.14.1",
"mysql": "^2.11.1",
"mysql2": "^1.0.0-rc.12",
"redis": "^2.6.2",
"superagent": "^2.2.0",
"ursa": "^0.9.4",
"utf-8-validate": "^1.2.1",
"uuid": "^2.0.2",
"ws": "^1.1.1"
}