Error when typing in Atom/Nteract: "{Current Date/Time} Unhandled shell message: complete_request"

As the title says, any time I type in a Go file in Atom after running a line with gophernotes I get an error like this
`2018/04/07 11:17:46 Unhandled shell message: complete_request`

This shows up in the top-right as a bubble, like most messages in Atom. When I select "show debug messages" in the Hydrogen settings, and display the console, nothing of relevance shows up. The kernel seems to work, but those messages make it very difficult to actually write the code.

先在使用 gophernotes 运行一行代码后，于 Atom 或 Nteract 中重现该错误，然后跟踪 kernel 如何处理 `complete_request` shell 消息。完成的标准是输入时不再产生未处理消息气泡，同时 kernel 仍能继续工作。

由索引模型根据 Issue 内容生成。