Upgrading actix-web

[antiblue]

Hi all, I started working on upgrading the Actix-Web parts, but I stumble over an issue with Tokio.

Through OPCUASession.connect the function get_server_endpoints_from_url<T> is called and at the end an instance of Session is dropped. This causes a panic, because Tokio wants to enter a blocking region:

thread 'actix-rt|system:0|arbiter:3' panicked at 'Cannot drop a runtime in a context where blocking is not allowed. This happens when a runtime is dropped from within an asynchronous context.', ...tokio-1.32.0\src\runtime\blocking\shutdown.rs:51:21

I have found running-actix-web-using-tokiomain in Actix-Web's documentation, stating that block_in_place will not work. Unfortunately the backtrace reveals exactly that:

  13: core::ptr::drop_in_place<opcua::client::session::session::Session>
             at /rustc/5680fa18feaa87f3ff04063800aec256c3d4b4be\library\core\src\ptr\mod.rs:497
  14: opcua::client::client::Client::get_server_endpoints_from_url<ref$<str$> >
             at ...\opcua\lib\src\client\client.rs:493

Any suggestions on how to fix this?

(The code has been forked here)