init {
    // Put a floor on the keep alive duration, otherwise cleanup will spin loop.
    require(keepAliveDuration > 0L) { "keepAliveDuration <= 0: $keepAliveDuration" }
  }

  fun idleConnectionCount(): Int {
    return connections.count {
      it.withLock { it.calls.isEmpty() }
    }
  }

  fun connectionCount(): Int {
    return connections.size
  }

  /**

      }
  }

  @Test
  fun connectionPool() {
    var connectionPool = ConnectionPool()
    connectionPool = ConnectionPool(0, 0L, TimeUnit.SECONDS)
    val idleConnectionCount: Int = connectionPool.idleConnectionCount()
    val connectionCount: Int = connectionPool.connectionCount()
    connectionPool.evictAll()
  }

  @Test
  fun connectionSpec() {