Add some data-flows jargon notes (re: #270)

piker/data/flows.py

@@ -15,9 +15,10 @@
 # along with this program.  If not, see <https://www.gnu.org/licenses/>.
 
 """
-Real-time data flow abstractions.
+abstractions for organizing, managing and generally operating-on
+real-time data processing data-structures.
 
-<writeup on "buffers, streams, flumes and flows..">
+"Streams, flumes, cascades and flows.."
 
 """
 from contextlib import asynccontextmanager as acm
@@ -52,6 +53,26 @@ if TYPE_CHECKING:
     from .feed import Feed
 
 
+# TODO: ideas for further abstractions as per
+# https://github.com/pikers/piker/issues/216 and
+# https://github.com/pikers/piker/issues/270:
+# - a ``Cascade`` would be the minimal "connection" of 2 ``Flumes``
+#   as per circuit parlance:
+#   https://en.wikipedia.org/wiki/Two-port_network#Cascade_connection
+#     - could cover the combination of our `FspAdmin` and the
+#       backend `.fsp._engine` related machinery to "connect" one flume
+#       to another?
+# - a (financial signal) ``Flow`` would be the a "collection" of such
+#    minmial cascades. Some engineering based jargon concepts:
+#     - https://en.wikipedia.org/wiki/Signal_chain
+#     - https://en.wikipedia.org/wiki/Daisy_chain_(electrical_engineering)
+#     - https://en.wikipedia.org/wiki/Audio_signal_flow
+#     - https://en.wikipedia.org/wiki/Digital_signal_processing#Implementation
+#     - https://en.wikipedia.org/wiki/Dataflow_programming
+#     - https://en.wikipedia.org/wiki/Signal_programming
+#     - https://en.wikipedia.org/wiki/Incremental_computing
+
+
 class Flume(Struct):
     '''
     Composite reference type which points to all the addressing handles