CurrentFiber
The current fiber flag determines whether or not the ZIO runtime system
will store the current fiber inside a ThreadLocal whenever a fiber begins
executing on a thread. Use of this flag will negatively impact performance,
but is essential where interop with ThreadLocal is required.
trait Singleton
trait Product
trait Mirror
trait Serializable
trait Product
trait Equals
trait RuntimeFlag
class Object
trait Matchable
class Any
CurrentFiber.type