sausage-plugin part 2: import! with typed clients (sausage_interface::client_rs), TCP endpoints with rpc.endpoint, examples

Part 1 fixes: complete stdout writes, buffered stdin, Rust type names
in schemas, enum variant docs, -32603 for serde errors in handlers,
crate docs and modules. End-to-end check of a generated consumer through
a fake core.

examples/consumer/src/main.rs

@@ -0,0 +1,47 @@
+//! Use typed calls from discovered provider documents in `imports/`.
+//! Copy fresh documents from `/proc/core/plugins/<provider>/discover.json` after an interface changes.
+use sausage_plugin::{Result, rpc, schema};
+sausage_plugin::import!("notes");
+sausage_plugin::import!("www");
+sausage_plugin::import!("secrets");
+struct Consumer;
+/// The text and HTTP port for this demonstration.
+#[schema]
+struct DemoParams {
+    /// The note text to append.
+    text: String,
+    /// The port for the detached HTTP server.
+    port: u16,
+}
+#[rpc]
+impl Consumer {
+    /// Add a note, start a server, and inspect its control endpoint.
+    async fn demo(&self, p: DemoParams) -> Result<u64> {
+        let added = notes::add(notes::AddParams { text: p.text }).await?;
+        eprintln!("{} notes", added.count);
+        let pid = www::start(www::StartParams { port: p.port })
+            .detach()
+            .await?;
+        let control = www::control::connect(format!("/proc/{pid}/control")).await?;
+        control.stats().await
+    }
+    /// Store and read a value through the boot service's fixed endpoint.
+    async fn vault(&self) -> Result<Option<String>> {
+        let vault = secrets::vault::connect("/run/secrets").await?;
+        vault
+            .put(secrets::PutParams {
+                name: "example".into(),
+                value: "hello".into(),
+            })
+            .on_notify(|name, params| eprintln!("{name}: {params}"))
+            .await?;
+        vault
+            .get(secrets::GetParams {
+                name: "example".into(),
+            })
+            .await
+    }
+}
+fn main() {
+    sausage_plugin::run(Consumer)
+}