Cancel render operation when view is released

Author: pjay

CHANGELOG.md

@@ -13,6 +13,10 @@ All notable changes to this project will be documented in this file.
   - Added by [William Entriken](https://github.com/fulldecent) in Regards to Issue
   [#76](https://github.com/fulldecent/FDWaveformView/issues/86).
 
+#### Fixed
+- Cancel waveform render operation when view is released
+  - Added by [Philippe Jayet](https://github.com/pjay)
+
 ---
 
 ## [2.2.0](https://github.com/fulldecent/FDWaveformView/releases/tag/2.2.0)

Source/FDWaveformView.swift

@@ -304,6 +304,10 @@ open class FDWaveformView: UIView {
         super.init(frame: rect)
         setup()
     }
+    
+    deinit {
+        inProgressWaveformRenderOperation?.cancel()
+    }
 
     /// If the cached waveform or in progress waveform is insufficient for the current frame
     fileprivate func cacheStatus() -> CacheStatus {