func (s *Singleton[T]) GetNonBlocking() *T {
	select {
	case <-s.set:
		return s.v
	default:
		return nil
	}
}

// IsSet will return whether the singleton has been set.
func (s *Singleton[T]) IsSet() bool {
	select {
	case <-s.set:
		return true
	default:
		return false
	}
}

// Set the value and unblock all Get requests.

			continue
		}

		var isSet bool
		for _, userMetadataPrefix := range userMetadataKeyPrefixes {
			if !stringsHasPrefixFold(k, userMetadataPrefix) {
				continue
			}
			w.Header()[strings.ToLower(k)] = []string{v}
			isSet = true
			break
		}

		if !isSet {
			w.Header().Set(k, v)
		}
	}

	var start, rangeLen int64

    }

    val bit = 1 shl id
    set = set or bit
    values[id] = value
    return this
  }

  /** Returns true if a value has been assigned for the setting `id`. */
  fun isSet(id: Int): Boolean {
    val bit = 1 shl id
    return set and bit != 0
  }

  /** Returns the value for the setting `id`, or 0 if unset. */
  operator fun get(id: Int): Int = values[id]

	}
	return w.Flush()
}

func configSource(flag string, v env.VariableInfo) string {
	// Environment variables have high precedence in Viper
	if v.IsSet() {
		return "$" + v.GetName()
	}

	if viper.InConfig(flag) {
		return root.IstioConfig
	}

	return "default"

import assertk.assertions.isFalse
import assertk.assertions.isTrue
import org.junit.jupiter.api.Test

class SettingsTest {
  @Test
  fun unsetField() {
    val settings = Settings()
    assertThat(settings.isSet(Settings.MAX_CONCURRENT_STREAMS)).isFalse()
    assertThat(settings.getMaxConcurrentStreams()).isEqualTo(Int.MAX_VALUE)
  }

  @Test
  fun setFields() {
    val settings = Settings()