了解命名管道行为

Question

我有一些像这样的shell代码：

rm -f myfifo && mkfifo myfifo
(
    echo "data1" > myfifo
    echo "wrote first"
    echo "data2" > myfifo
    echo "wrote second"
) &

read -r ONE <myfifo
echo "$ONE" 
read -r TWO <myfifo
echo "$TWO"

我希望我会得到以下输出：

wrote first
data1
wrote second
data2

但是我得到以下输出：

wrote first
wrote second
data1

然后它永远挂起。 关于命名管道，我不了解什么原则？

谢谢。