with.swift

@discardableResult
@inlinable
private func with<T>(_ value: T, _ builder: (T) throws -> Void) rethrows -> T {
    try builder(value)
    return value
}

// Use
class MyClass {
    var prop = "it's"
    init() {}
}
let instance = with(MyClass()) {
    $0.prop += " awesome"
}

print(instance.prop) //"it's awesome"