fix: implements flushes in all writer

.github/workflows/build.yml

@@ -31,7 +31,7 @@ jobs:
   unit-test:
     strategy:
       matrix:
-        go-version: [ 1.16.x, 1.17.x, 1.18.x ]
+        go-version: [ 1.16.x, 1.17.x, 1.18.x, 1.19.x ]
 
     name: Unit test
     runs-on: ubuntu-latest

writer.go

@@ -138,6 +138,11 @@ func (m *LeveledWriter) Write(msg []byte) (int, error) {
 	return m.Default.Write(msg)
 }
 
+// Flush flushes the data
+func (m *LeveledWriter) Flush() error {
+	return m.Default.Flush()
+}
+
 // DeduplicatorWriter is a Writer which deduplicate fields with the same name
 type DeduplicatorWriter struct {
 	Default Writer
@@ -183,6 +188,11 @@ func (m *DeduplicatorWriter) Write(msg []byte) (int, error) {
 	return m.Default.Write(msg)
 }
 
+// Flush flushes the data
+func (m *DeduplicatorWriter) Flush() error {
+	return m.Default.Flush()
+}
+
 // MultiWriter is a Writer which based on the log level will write to a writer
 // It also uses a Default one for the Write method
 // as well as supporting the case when the Writer is not found in the Level map