Introduced dylib extension format, cleared up shutdown sequence

orchid-extension/src/tokio.rs

@@ -10,7 +10,7 @@ use crate::ext_port::ExtPort;
 /// value returned by [crate::system_ctor::SystemCtor::inst] to initiate
 /// shutdown.
 #[cfg(feature = "tokio")]
-pub async fn tokio_main(builder: ExtensionBuilder) -> ! {
+pub async fn tokio_entrypoint(builder: ExtensionBuilder) {
 	use tokio::io::{stderr, stdin, stdout};
 	use tokio::task::{LocalSet, spawn_local};
 	use tokio_util::compat::{TokioAsyncReadCompatExt, TokioAsyncWriteCompatExt};
@@ -27,5 +27,12 @@ pub async fn tokio_main(builder: ExtensionBuilder) -> ! {
 		});
 	});
 	local_set.await;
-	std::process::exit(0)
+}
+
+#[macro_export]
+macro_rules! tokio_main {
+	($builder:expr) => {
+		#[tokio::main]
+		pub async fn main() { $crate::tokio::tokio_entrypoint($builder).await }
+	};
 }