Bumped sdk version, updated deps, improved code.

`Eterl` nows implements `Codec`

README.md

@@ -3,6 +3,7 @@
 Eterl is a fast packer and unpacker for the External Term Erlang Format (version 131).
 
 ## Example
+
 ```dart
 import 'package:eterl/eterl.dart';
 
@@ -25,3 +26,33 @@ void main() {
 - `Map`s
 - `List`s
 - `Tuple`s (only while decoding, tuples are converted into a `List`)
+
+## Benchmarks
+
+`dart run benchmark/eterl_benchmark.dart`
+
+```shell
+[210ms:142us] Encoder: hello world
+  mean: 0.15 ± 0.11 us, median: 0.13 ± 0.017 us
+  ▉▂▄▂__________  110  _____ sample size: 100 (averaged over 225 runs)
+
+[243ms:186us] Encoder: data
+  mean: 2.59 ± 0.76 us, median: 2.28 ± 0.24 us
+  ▆▉▄▂________________▁_______ sample size: 79 (averaged over 199 runs)
+
+[274ms:047us] Encoder: Complex data
+  mean: 49.75 ± 12.45 us, median: 42.58 ± 14.93 us
+  ▉▁▁▁_ sample size: 28 (averaged over 46 runs)
+
+[206ms:551us] Decoder: hello world
+  mean: 0.23 ± 0.12 us, median: 0.17 ± 0.10 us
+  ▉_▄▁_____________ sample size: 100 (averaged over 188 runs)
+
+[243ms:790us] Decoder: data
+  mean: 3.60 ± 1.17 us, median: 2.91 ± 1.46 us
+  ▉▆▁▁▃_ sample size: 75 (averaged over 165 runs)
+
+[266ms:378us] Decoder: Complex data
+  mean: 158.66 ± 312.078 us, median: 63.87 ± 12.28 us
+  ▉▅▁_▁____  149  _____ sample size: 27 (averaged over 28 runs)
+```