SMP protocol: optimize batching transactions, remove Builder (#961)

* remove Builder

* fewer chunks

* remove lazy bytestrings

* optimize

* pad

src/Simplex/Messaging/Crypto.hs

@@ -140,7 +140,6 @@ module Simplex.Messaging.Crypto
 
     -- * Message padding / un-padding
     pad,
-    pad',
     unPad,
 
     -- * X509 Certificates
@@ -206,8 +205,6 @@ import Database.SQLite.Simple.FromField (FromField (..))
 import Database.SQLite.Simple.ToField (ToField (..))
 import GHC.TypeLits (ErrorMessage (..), KnownNat, Nat, TypeError, natVal, type (+))
 import Network.Transport.Internal (decodeWord16, encodeWord16)
-import Simplex.Messaging.Builder (Builder, byteString, word16BE)
-import qualified Simplex.Messaging.Builder as BB
 import Simplex.Messaging.Encoding
 import Simplex.Messaging.Encoding.String
 import Simplex.Messaging.Parsers (blobFieldDecoder, parseAll, parseString)
@@ -922,14 +919,6 @@ pad msg paddedLen
     len = B.length msg
     padLen = paddedLen - len - 2
 
-pad' :: Builder -> Int -> Either CryptoError Builder
-pad' msg paddedLen
-  | len <= maxMsgLen && padLen >= 0 = Right $ word16BE (fromIntegral len) <> msg <> byteString (B.replicate padLen '#')
-  | otherwise = Left CryptoLargeMsgError
-  where
-    len = BB.length msg
-    padLen = paddedLen - len - 2
-
 unPad :: ByteString -> Either CryptoError ByteString
 unPad padded
   | B.length lenWrd == 2 && B.length rest >= len = Right $ B.take len rest