feat: userspace program loading and task spawning

userspace/client/src/main.rs

@@ -7,15 +7,18 @@ use dusk_sys::{println, sys_exit, sys_recv, sys_send};
 pub extern "C" fn _start() -> ! {
     let msg = "Hello from client!";
     println!("[client] Sent: {}", msg);
-    sys_send(0, msg.as_ptr() as usize, msg.len()).unwrap();
+    // TODO: we assume the echo server is task 1 (spawned by omega3)
+    sys_send(1, msg.as_ptr() as usize, msg.len()).unwrap();
+
     let out = [0u8; 128];
     let out_ptr = out.as_ptr() as usize;
     let max_len = out.len();
-    let (actual_len, sender) = sys_recv(out_ptr, max_len).unwrap();
+    let (actual_len, _) = sys_recv(out_ptr, max_len).unwrap();
     println!(
         "[client] Received: {}",
         core::str::from_utf8(&out[..actual_len]).unwrap()
     );
+
     sys_exit(0);
 }