Display a message when the execution service can't be reached.

[jrusbatch]

If an error occurs during the SignalR request to execute the code, an error message should be displayed to the user letting them know that code execution services are having temporary problems.

This message should be friendly and unobtrusive.

[jrusbatch]

Alternatively, an indicator could be added to the page to display the "health" of the workers. For example, a small circle that is red to indicate code execution is not available (ex. workers aren't responding), yellow to indicate that there may be a delay while executing code (ex. workers are under heavy load), or green to indicate that everything should be working normally.

But, the aim of the service is to make execution feel as instantaneous as possible, and an indicator like this might betray that illusion.