Errors when closing logger with syslog transport

[bbusschots-mu]

When I call .close() on a logger with a syslog transport the following error is thrown:

failed to close logger TypeError: self.socket.close is not a function
    at _close (/Users/bart/Documents/Temp/fromMUGit/moodle-integration-33/node_modules/winston-syslog/lib/winston-syslog.js:227:21)
    at exports.Syslog.Syslog.close (/Users/bart/Documents/Temp/fromMUGit/moodle-integration-33/node_modules/winston-syslog/lib/winston-syslog.js:236:4)
    at /Users/bart/Documents/Temp/fromMUGit/moodle-integration-33/node_modules/winston/lib/winston/logger.js:405:17
    at Array.forEach (native)
    at exports.Logger.Logger.close (/Users/bart/Documents/Temp/fromMUGit/moodle-integration-33/node_modules/winston/lib/winston/logger.js:402:15)
...

[yuvipanda]

I get this too, preventing use of tcp for logging:

/home/yuvipanda/code/jupyterhub-loadtest/node_modules/winston-syslog/lib/winston-syslog.js:201
          this.socket.close();
                      ^

TypeError: this.socket.close is not a function
    at Timeout._close [as _onTimeout] (/home/yuvipanda/code/jupyterhub-loadtest/node_modules/winston-syslog/lib/winston-syslog.js:201:23)
    at ontimeout (timers.js:475:11)
    at tryOnTimeout (timers.js:310:5)
    at Timer.listOnTimeout (timers.js:270:5)