Add concise readme example

examples/parallelism/we_are_processes.py

@@ -0,0 +1,34 @@
+"""
+Run with a process monitor from a terminal using:
+$TERM -e watch -n 0.1  "pstree -a $$" & python examples/parallelism/we_are_processes.py || kill $!
+
+"""
+from multiprocessing import cpu_count
+import os
+
+import tractor
+import trio
+
+
+async def target():
+    print(f"Yo, i'm {tractor.current_actor().name} "
+          f"running in pid {os.getpid()}")
+    await trio.sleep_forever()
+
+
+async def main():
+
+    async with tractor.open_nursery() as n:
+
+        for i in range(cpu_count()):
+            await n.run_in_actor(target, name=f'worker_{i}')
+
+        print('This process tree will self-destruct in 1 sec...')
+        await trio.sleep(1)
+
+        # you could have done this yourself
+        raise Exception('Self Destructed')
+
+
+if __name__ == '__main__':
+    trio.run(main)