====== Windowing (Streaming Analytics) ======

**What it is:** Grouping streaming events into time-based “windows” for calculations.

**What it’s for:**
  * Compute metrics like “average speed per 1 minute” or “count events per 5 minutes”.
  * Make continuous streams measurable in time slices.

**Common window examples:**
  * Tumbling window (non-overlapping): every 1 minute
  * Sliding window (overlapping): last 5 minutes updated every 1 minute

**Exam cues:**
  * “compute metric per minute / per time interval” → windowing.

**Hard words:**
  * *window* /ˈwɪndoʊ/: cửa sổ thời gian
  * *tumbling* /ˈtʌmblɪŋ/: rời rạc (không chồng lấn)
  * *sliding* /ˈslaɪdɪŋ/: trượt (có chồng lấn)
  * *interval* /ˈɪntərvl/: khoảng thời gian