You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: syscall_freebsd_amd64.go
    path of file: ./repos/teller/vendor/golang.org/x/sys/unix
    
    the code of the file until where you have to start completion: // Copyright 2009 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.

//go:build amd64 && freebsd
// +build amd64,freebsd

package unix

import (
	"syscall"
	"unsafe"
)

func se
    
func sendfile(outfd int, infd int, offset *int64, count int) (written int, err error) {
	var writtenOut uint64 = 0
	_, _, e1 := Syscall9(SYS_SENDFILE, uintptr(infd), uintptr(outfd), uintptr(*offset), uintptr(count), 0, uintptr(unsafe.Pointer(&writtenOut)), 0, 0, 0)

	written = int(writtenOut)

	if e1 != 0 {
		err = e1
	}
	return
}