docs: 完善代码文档和注释，添加使用示例

main.go

@@ -1,23 +1,46 @@
-// Package goemitter
+// Package goemitter implements an event emitter pattern similar to Node.js EventEmitter.
+// It provides a way to register event listeners and emit events with data.
+//
+// Basic usage example:
+//
+//	emitter := goemitter.NewEmitter()
+//
+//	// Register an event listener
+//	handle := emitter.On("userConnected", func(args ...interface{}) {
+//	    user := args[0].(string)
+//	    fmt.Printf("User connected: %s\n", user)
+//	})
+//
+//	// Emit an event
+//	emitter.Emit("userConnected", "john_doe")
+//
+//	// Remove the listener when no longer needed
+//	handle.Remove()
 package goemitter
 
 import (
 	"sync"
 )
 
+// EventEmitter provides event subscription and publishing functionality.
+// It is safe for concurrent use thanks to internal synchronization.
 type EventEmitter struct {
-	callbacks     map[string]map[int]func(args ...interface{})
-	onceCallbacks map[string][]func(args ...interface{})
-	lock          sync.Mutex
-	counter       int
+	callbacks     map[string]map[int]func(args ...interface{}) // Persistent event callbacks indexed by ID
+	onceCallbacks map[string][]func(args ...interface{})       // One-time event callbacks
+	lock          sync.Mutex                                   // Mutex to ensure thread safety
+	counter       int                                          // Counter for generating unique callback IDs
 }
 
+// EventHandle represents a handle to a registered event listener.
+// It can be used to remove the listener when it's no longer needed.
 type EventHandle struct {
-	id      int
-	event   string
-	emitter *EventEmitter
+	id      int           // Unique identifier for the callback
+	event   string        // Event name
+	emitter *EventEmitter // Reference to the parent emitter
 }
 
+// Remove unregisters the event listener associated with this handle.
+// After removal, the listener will no longer receive events.
 func (eh *EventHandle) Remove() {
 	eh.emitter.lock.Lock()
 	defer eh.emitter.lock.Unlock()
@@ -26,6 +49,9 @@ func (eh *EventHandle) Remove() {
 	}
 }
 
+// On registers a new event listener for the specified event.
+// It returns an EventHandle that can be used to remove the listener later.
+// The callback function can accept any number of arguments passed during event emission.
 func (e *EventEmitter) On(event string, callback func(args ...interface{})) *EventHandle {
 	e.lock.Lock()
 	defer e.lock.Unlock()
@@ -41,6 +67,9 @@ func (e *EventEmitter) On(event string, callback func(args ...interface{})) *Eve
 	}
 }
 
+// Once registers a one-time event listener for the specified event.
+// The listener will be automatically removed after being triggered once.
+// Multiple one-time listeners can be registered for the same event.
 func (e *EventEmitter) Once(event string, callback func(args ...interface{})) {
 	e.lock.Lock()
 	defer e.lock.Unlock()
@@ -52,44 +81,55 @@ func (e *EventEmitter) Once(event string, callback func(args ...interface{})) {
 	}
 }
 
+// Emit triggers an event asynchronously with the provided arguments.
+// All registered callbacks for the event will be executed in separate goroutines.
+// One-time callbacks are cleared after emission.
 func (e *EventEmitter) Emit(event string, data ...interface{}) {
 	e.lock.Lock()
 	defer e.lock.Unlock()
 
+	// Execute persistent callbacks asynchronously
 	if callbacks, ok := e.callbacks[event]; ok {
 		for _, callback := range callbacks {
 			go callback(data...)
 		}
 	}
 
+	// Execute and clear one-time callbacks
 	if onceCallbacks, ok := e.onceCallbacks[event]; ok {
 		for _, callback := range onceCallbacks {
 			go callback(data...)
-
 		}
 		e.onceCallbacks[event] = []func(args ...interface{}){}
 	}
 }
 
+// EmitSync triggers an event synchronously with the provided arguments.
+// All registered callbacks for the event will be executed in the current goroutine.
+// One-time callbacks are cleared after emission.
 func (e *EventEmitter) EmitSync(event string, data ...interface{}) {
 	e.lock.Lock()
 	defer e.lock.Unlock()
 
+	// Execute persistent callbacks synchronously
 	if callbacks, ok := e.callbacks[event]; ok {
 		for _, callback := range callbacks {
 			callback(data...)
 		}
 	}
 
+	// Execute and clear one-time callbacks
 	if onceCallbacks, ok := e.onceCallbacks[event]; ok {
 		for _, callback := range onceCallbacks {
 			callback(data...)
-
 		}
 		e.onceCallbacks[event] = []func(args ...interface{}){}
 	}
 }
 
+// NewEmitter creates and initializes a new EventEmitter instance.
+// It initializes the internal maps for storing callbacks and returns
+// a pointer to the new instance.
 func NewEmitter() *EventEmitter {
 	ret := &EventEmitter{}
 	ret.callbacks = make(map[string]map[int]func(args ...interface{}))