Lazy.kt

<!-- Copyright 2020 Google LLC.
SPDX-License-Identifier: Apache-2.0 -->

override val value: T
   get() {
       val _v1 = _value
       if (_v1 !== UNINITIALIZED_VALUE) {
           @Suppress("UNCHECKED_CAST")
           return _v1 as T
       }

       return synchronized(lock) {
           val _v2 = _value
           if (_v2 !== UNINITIALIZED_VALUE) {
               @Suppress("UNCHECKED_CAST") (_v2 as T)
           } else {
               val typedValue = initializer!!()
               _value = typedValue
               initializer = null
               typedValue
           }
       }
   }