README: add logger type doc and updated benchmarks

README.md

@@ -1,14 +1,24 @@
 # Benchmark for Logging With Zap
 
+## Logger Types
+### Discarded Logger
+Sends all the writes to ioutil.Discard
+### Sampled Logger
+Creates a zap core that samples incoming N (here is 10) entries, with a given level and message
+each tick. If more Entries with the same level and message are seen during the same interval, every Mth message is logged and the rest are dropped.
+### Writer Logger
+Sneds all the writes to a writer (stderr) without sampling.
+### WriterSampler
+Writer Logger with a sampler.
+
 ## Benchmark Results
-on my MacBook Pro
 ```
-➜  BenchmarkZapLoggers git:(master) ✗ go test -bench=. 
-goos: darwin
-goarch: amd64
-pkg: github.com/rezakamalifard/BenchmarkZapLoggers
-BenchmarkSugarLogger-4            793906              1260 ns/op             512 B/op          1 allocs/op
-BenchmarkStructuredLogger-4      1262098               950 ns/op             256 B/op          1 allocs/op
-PASS
-ok      github.com/rezakamalifard/BenchmarkZapLoggers    3.575s
+BenchmarkDiscardedSugarLogger                817209           1292 ns/op         512 B/op          1 allocs/op
+BenchmarkDiscardedStructuredLogger           1000000          1010 ns/op         256 B/op          1 allocs/op
+BenchmarkSampledSugarLogger                  3972433          277 ns/op          51 B/op           0 allocs/op
+BenchmarkSampledStructuredLogger             3486465          356 ns/op          256 B/op          1 allocs/op
+BenchmarkWriterSugarLogger                   85296            14986 ns/op        760 B/op          4 allocs/op
+BenchmarkWriterStructuredLogger              57351            17587 ns/op        504 B/op          4 allocs/op
+BenchmarkWriterSamplerSugarLogger            3176926          563 ns/op          7 B/op            0 allocs/op
+BenchmarkWriterSamplerStructuredLogger       2051127          610 ns/op          258 B/op          1 allocs/op
 ```