val candidate = connectionUser.candidateConnection() ?: return null

    // Make sure this connection is healthy & eligible for new exchanges. If it's no longer needed
    // then we're on the hook to close it.
    val healthy = candidate.isHealthy(connectionUser.doExtensiveHealthChecks())
    var noNewExchangesEvent = false
    val toClose: Socket? =
      candidate.withLock {
        when {
          !healthy -> {

      if (connection.isHealthy(doExtensiveHealthChecks)) return connection

      // In the second synchronized block, release the unhealthy acquired connection. We're also on
      // the hook to close this connection if it's no longer in use.
      val noNewExchangesEvent: Boolean
      val toClose: Socket? =
        connection.withLock {
          noNewExchangesEvent = !connection.noNewExchanges