ntf server: better batching and logging (#780)

* ntf server: better batching and logging

* reduce batch delay for ntf server

* comments

* 5.1.3, ntf 1.4.2

* more logging

* more logging

* split large batches, more logging

* remove some logs

src/Simplex/Messaging/Util.hs

@@ -18,6 +18,7 @@ import qualified Data.Text as T
 import Data.Text.Encoding (decodeUtf8With)
 import Data.Time (NominalDiffTime)
 import UnliftIO.Async
+import Data.List (groupBy, sortOn)
 
 raceAny_ :: MonadUnliftIO m => [m a] -> m ()
 raceAny_ = r []
@@ -102,6 +103,17 @@ eitherToMaybe :: Either a b -> Maybe b
 eitherToMaybe = either (const Nothing) Just
 {-# INLINE eitherToMaybe #-}
 
+groupOn :: Eq k => (a -> k) -> [a] -> [[a]]
+groupOn = groupBy . eqOn
+    -- it is equivalent to groupBy ((==) `on` f),
+    -- but it redefines `on` to avoid duplicate computation for most values.
+    -- source: https://hackage.haskell.org/package/extra-1.7.13/docs/src/Data.List.Extra.html#groupOn
+    -- the on2 in this package is specialized to only use `==` as the function, `eqOn f` is equivalent to `(==) `on` f`
+    where eqOn f = \x -> let fx = f x in \y -> fx == f y
+
+groupAllOn :: Ord k => (a -> k) -> [a] -> [[a]]
+groupAllOn f = groupOn f . sortOn f
+
 safeDecodeUtf8 :: ByteString -> Text
 safeDecodeUtf8 = decodeUtf8With onError
   where