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: write_err_android.go
    path of file: ./repos/gccrs/libgo/go/runtime
    
    the code of the file until where you have to start completion: // Copyright 2014 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.

package runtime

import "unsafe"

var (
	writeHeader = []byte{6 /* ANDROID_LOG_ERROR */, 'G', 'o', 0}
	writePath   = []byte("/dev/log/main\x00")
	writeLogd   = []byte("/dev/socket/logdw\x00")

	// guarded by printlock/printunlock.
	writeFD 
    
func writeErr(b []byte) {
	if logger == unknown {
		// Use logd if /dev/socket/logdw is available.
		if v := uintptr(access(&writeLogd[0], 0x02 /* W_OK */)); v == 0 {
			logger = logd
			initLogd()
		} else {
			logger = legacy
			initLegacy()
		}
	}

	// Write to stderr for command-line programs.
	write(2, unsafe.Pointer(&b[0]), int32(len(b)))

	// Log format: "<header>\x00<message m bytes>\x00"
	//
	// <header>
	//   In legacy mode: "<priority 1 byte><tag n bytes>".
	//   In logd mode: "<android_log_header_t 11 bytes><priority 1 byte><tag n bytes>"
	//
	// The entire log needs to be delivered in a single syscall (the NDK
	// does this with writev). Each log is its own line, so we need to
	// buffer writes until we see a newline.
	var hlen int
	switch logger {
	case logd:
		hlen = writeLogdHeader()
	case legacy:
		hlen = len(writeHeader)
	}

	dst := writeBuf[hlen:]
	for _, v := range b {
		if v == 0 { // android logging won't print a zero byte
			v = '0'
		}
		dst[writePos] = v
		writePos++
		if v == '\n' || writePos == len(dst)-1 {
			dst[writePos] = 0
			write(writeFD, unsafe.Pointer(&writeBuf[0]), int32(hlen+writePos))
			for i := range dst {
				dst[i] = 0
			}
			writePos = 0
		}
	}
}