哪个 golang 框架最适合复杂应用程序开发？

package main

import (
    "github.com/gin-gonic/gin"
)

// Item represents a single item in the cart
type Item struct {
    Name  string
    Price float64
}

// Cart represents the collection of items in the cart
type Cart struct {
    Items []Item
}

func main() {
    // Create a new Gin engine
    router := gin.Default()

    // Create a new Cart instance
    cart := &Cart{}

    // Define routes for the cart API
    router.POST("/cart", addItems)
    router.DELETE("/cart/:item", deleteItem)
    router.GET("/cart", getCart)
    router.POST("/cart/checkout", checkout)

    // Start the server
    router.Run(":8080")
}

func addItems(c *gin.Context) {
    var items []Item
    if err := c.BindJSON(&items); err != nil {
        c.JSON(http.StatusBadRequest, gin.H{"error": err.Error()})
        return
    }
    cart.Items = append(cart.Items, items...)
    c.JSON(http.StatusOK, cart)
}

func deleteItem(c *gin.Context) {
    item := c.Param("item")
    for i, it := range cart.Items {
        if it.Name == item {
            cart.Items = append(cart.Items[:i], cart.Items[i+1:]...)
            c.JSON(http.StatusOK, cart)
            return
        }
    }
    c.JSON(http.StatusNotFound, gin.H{"error": "Item not found"})
}

func getCart(c *gin.Context) {
    c.JSON(http.StatusOK, cart)
}

func checkout(c *gin.Context) {
    total := 0.0
    for _, item := range cart.Items {
        total += item.Price
    }
    c.JSON(http.StatusOK, gin.H{"total": total})
}