How to use computed property in a codable struct (swift) : <p>I've created a "codable" struct to serialize a data set and encode it to Json. Everything is working great except the computed properties don't show in the json string. How can I include computed properties during the encode phase.</p>

<p>Ex:</p>

<pre><code>struct SolidObject:Codable{

    var height:Double                      = 0
    var width:Double                       = 0
    var length:Double                      = 0

    var volume:Double {
        get{
            return height * width * length
        }
    }
}

var solidObject = SolidObject()
solidObject.height = 10.2
solidObject.width = 7.3
solidObject.length = 5.0

let jsonEncoder = JSONEncoder()
do {
    let jsonData = try jsonEncoder.encode(solidObject)
    let jsonString = String(data: jsonData, encoding: .utf8)!
    print(jsonString)
} catch {
    print(error)
}
</code></pre>

<p>prints out "{"width":7.2999999999999998,"length":5,"height":10.199999999999999}"</p>

<p>I am also curious about having 7.29999.. instead of 7.3 but my main question is "how can I include "volume" to this json string too"?</p>
