Copy by default in ring buffer window

Changing the default is motivated by favouring data integrity over
performance concerns which are minor in the majority of the expected
applications.

Also make force_copy a keyword argument.

Signed-off-by: cwasicki <[email protected]>

Author: cwasicki

src/frequenz/sdk/timeseries/_ringbuffer/buffer.py

@@ -257,7 +257,7 @@ def datetime_to_index(
         )
 
     def window(
-        self, start: datetime, end: datetime, force_copy: bool = False
+        self, start: datetime, end: datetime, *, force_copy: bool = True
     ) -> FloatArray:
         """Request a view on the data between start timestamp and end timestamp.
 
@@ -266,7 +266,7 @@ def window(
 
         Will return a copy in the following cases:
         * The requested time period is crossing the start/end of the buffer.
-        * The force_copy parameter was set to True (default False).
+        * The force_copy parameter was set to True (default True).
 
         The first case can be avoided by using the appropriate
         `align_to` value in the constructor so that the data lines up
@@ -278,7 +278,7 @@ def window(
         Args:
             start: start time of the window.
             end: end time of the window.
-            force_copy: optional, default False. If True, will always create a
+            force_copy: optional, default True. If True, will always create a
                 copy of the data.
 
         Raises: