Add support for the logger private buffer pool.

logger.go

@@ -44,6 +44,9 @@ type Logger struct {
 	entryPool sync.Pool
 	// Function to exit the application, defaults to `os.Exit()`
 	ExitFunc exitFunc
+	// The buffer pool used to format the log. If it is nil, the default global
+	// buffer pool will be used.
+	BufferPool BufferPool
 }
 
 type exitFunc func(int)
@@ -402,3 +405,10 @@ func (logger *Logger) ReplaceHooks(hooks LevelHooks) LevelHooks {
 	logger.mu.Unlock()
 	return oldHooks
 }
+
+// SetBufferPool sets the logger buffer pool.
+func (logger *Logger) SetBufferPool(pool BufferPool) {
+	logger.mu.Lock()
+	defer logger.mu.Unlock()
+	logger.BufferPool = pool
+}