I haven't been able to find much documentation on the isolation of Azure functions in an app service plan.
If you share a static variable for example an HttpClient between azure function invocations I presume reading through the scalability suggestions that it could run in the same process or separate processes or separate servers... which is fine, using Lazy<T> can help with threading issues.
But could separate Azure Functions share a worker process? i.e. should I isolate static variables to ensure isolation of the functions? I gather using a ConcurrentDictionary with a key for the function is a good approach to help solve this, but I haven't found any documentation that discusses isolation.