type hchan struct {
	qcount   uint           // total data in the queue
	dataqsiz uint           // size of the circular queue
	buf      unsafe.Pointer // points to an array of dataqsiz elements
	elemsize uint16
	closed   uint32
	timer    *timer // timer feeding this chan
	elemtype *_type // element type
	sendx    uint   // send index
	recvx    uint   // receive index
	recvq    waitq  // list of recv waiters
	sendq    waitq  // list of send waiters
	bubble   *synctestBubble

	// lock protects all fields in hchan, as well as several
	// fields in sudogs blocked on this channel.
	//
	// Do not change another G's status while holding this lock
	// (in particular, do not ready a G), as this can deadlock
	// with stack shrinking.
	lock mutex
}

package main

import "fmt"

func main() {
    ch := make(chan int, 1)  // ch 本质是 *hchan 指针，指向堆上一块内存

    go func() {
        ch <- 42            // 闭包捕获
    }()

    go func(ch chan int) {
        v := <-ch           // 值传递
        fmt.Println(v)
    }(ch)
}