从groovy运行curl时，是否将输出发送到error而不是stdout (进程)？

def command = ["curl", "http://example.com"]
def processBuilder = new ProcessBuilder(command)
processBuilder.redirectErrorStream(true) // 将标准错误流重定向到标准输出流
def process = processBuilder.start()

def reader = new BufferedReader(new InputStreamReader(process.getInputStream()))
def output = new StringBuilder()
String line
while ((line = reader.readLine()) != null) {
    output.append(line)
}

process.waitFor()
println output.toString() // 输出curl命令的结果