While toying around with Azure Functions for some app idea, I came across some documentation on best practices for using it.
The article continues further into detail on Patterns and Practices HTTP Performance Optimizations where I discovered something about HttpClient I would have never guessed:
[HttpClient is] intended to be instantiated once and reused throughout the lifetime of an application. However, it’s a common misunderstanding that these classes should be acquired only as necessary and released quickly
HttpClientobject is created for each user request. Under heavy load, the web server may exhaust the number of available sockets, resulting in
The HttpClient class is designed to be shared rather than pooled
Well whaddayaknow, until know I have always designed my applications to keep the HttpClient as short-lived as possible, always wrapping it in a using block to ensure proper disposal.
Turns out this is an anti-pattern, they actually advice you to create a static readonly HttpClient, which you reuse in your app.
Going to apply some improvements right now!