The value to check. 要检查的值
True if the value is an empty object, false otherwise. 如果值为空对象则返回 true，否则返回 false
This function uses for...in to enumerate enumerable string-keyed properties.
Symbol-keyed properties are skipped by for...in, so an object containing only Symbol-keyed properties
would be incorrectly reported as empty.
该函数使用 for...in 枚举可枚举的字符串键属性。
for...in 会跳过 Symbol 键属性，因此仅包含 Symbol 键属性的对象会被错误地报告为空。
Checks if the input is an empty object.
检查输入是否为空对象。