Refresh the Fibonnaci examples

* Change the examples to only seed with the value 1
  * The thread example blocks on emit due to the cycle in the stream
    so it CAN only seed with one value.
* Take all explicit references to Tornado out of the asyncio variant
* Suppress the stack spew from KeyboardException
* Ensure all variants have the same output

Author: dwskoog

examples/fib_asyncio.py

@@ -1,28 +1,17 @@
-from streamz import Stream
 import asyncio
-from tornado.platform.asyncio import AsyncIOMainLoop
-AsyncIOMainLoop().install()
+from streamz import Stream
 
 
-source = Stream()
+source = Stream(asynchronous=True)
 s = source.sliding_window(2).map(sum)
-L = s.sink_to_list()                    # store result in a list
-
-s.rate_limit(0.5).sink(source.emit)         # pipe output back to input
-s.rate_limit(1.0).sink(lambda x: print(L))  # print state of L every second
-
-source.emit(0)                          # seed with initial values
-source.emit(1)
-
+L = s.sink_to_list()                         # store result in a list
 
-def run_asyncio_loop():
-    loop = asyncio.get_event_loop()
-    try:
-        loop.run_forever()
-    except KeyboardInterrupt:
-        pass
-    finally:
-        loop.close()
+s.rate_limit('500ms').sink(source.emit)      # pipe output back to input
+s.rate_limit('1s').sink(lambda x: print(L))  # print state of L every second
 
+source.emit(1)                               # seed with initial values, does not block thread due to Future return
 
-run_asyncio_loop()
+try:
+    asyncio.get_event_loop().run_forever()
+except (KeyboardInterrupt, asyncio.CancelledError):
+    pass

examples/fib_thread.py

@@ -1,12 +1,13 @@
 from streamz import Stream
-from tornado.ioloop import IOLoop
 
 source = Stream()
 s = source.sliding_window(2).map(sum)
-L = s.sink_to_list()                    # store result in a list
+L = s.sink_to_list()                         # store result in a list
 
 s.rate_limit('500ms').sink(source.emit)      # pipe output back to input
 s.rate_limit('1s').sink(lambda x: print(L))  # print state of L every second
 
-source.emit(0)                          # seed with initial values
-source.emit(1)
+try:
+    source.emit(1)                           # seed with initial values, blocks thread due to cycle in stream
+except KeyboardInterrupt:
+    pass

examples/fib_tornado.py

@@ -4,12 +4,14 @@
 
 source = Stream(asynchronous=True)
 s = source.sliding_window(2).map(sum)
-L = s.sink_to_list()                    # store result in a list
+L = s.sink_to_list()                         # store result in a list
 
-s.rate_limit('500ms').sink(source.emit)         # pipe output back to input
+s.rate_limit('500ms').sink(source.emit)      # pipe output back to input
 s.rate_limit('1s').sink(lambda x: print(L))  # print state of L every second
 
-source.emit(0)                          # seed with initial values
-source.emit(1)
+source.emit(1)                               # seed with initial values, does not block thread due to Future return
 
-IOLoop.current().start()
+try:
+    IOLoop.current().start()
+except KeyboardInterrupt:
+    pass