Go Standard Library Cookbook

How to do it...

1. Open the console and create the folder chapter06/recipe04.
2. Navigate to the directory.
3. Create the syncwrite.go file with the following content:

        package main        import (          "fmt"          "io"          "os"          "sync"        )        type SyncWriter struct {          m sync.Mutex          Writer io.Writer        }        func (w *SyncWriter) Write(b []byte) (n int, err error) {          w.m.Lock()          defer w.m.Unlock()          return w.Writer.Write(b)        }        var data = []string{          "Hello!",          "Ola!",          "Ahoj!",        }        func main() {          f, err := os.Create("sample.file")          if err != nil {            panic(err)          }           wr := &SyncWriter{sync.Mutex{}, f}          wg := sync.WaitGroup{}          for _, val := range data {            wg.Add(1)            go func(greetings string) {              fmt.Fprintln(wr, greetings)              wg.Done()            }(val)          }          wg.Wait()        }

4. Execute the code by running go run syncwrite.go in the ...