/** Task for monitoring idle connections */
    private TimeoutTask connectionMonitorTask;

    /** Connection timeout in milliseconds */
    protected Integer connectionTimeout;

    /** Maximum total number of connections */
    protected Integer maxTotalConnections;

    /** Maximum connections per route */
    protected Integer maxConnectionsPerRoute;

import okhttp3.internal.toImmutableList

/**
 * A specification for a connection to an origin server. For simple connections, this is the
 * server's hostname and port. If an explicit proxy is requested (or [no proxy][Proxy.NO_PROXY] is
 * explicitly requested), this also includes that proxy information. For secure connections the
 * address also includes the SSL socket factory, hostname verifier, and certificate pinner.
 *

      printEvent("connectFailed");
    }

    @Override public void connectionAcquired(Call call, Connection connection) {
      printEvent("connectionAcquired");
    }

    @Override public void connectionReleased(Call call, Connection connection) {
      printEvent("connectionReleased");
    }

    @Override public void requestHeadersStart(Call call) {
      printEvent("requestHeadersStart");
    }

   * That may happen later by the connection pool thread.
   */
  fun cancel()

  /**
   * Carries an exchange. This is usually a connection, but it could also be a connect plan for
   * CONNECT tunnels. Note that CONNECT tunnels are significantly less capable than connections.
   */
  interface Carrier {
    val route: Route

    fun trackFailure(

      .assertLogMatch(Regex("""dnsEnd: \[.+]"""))
      .assertLogMatch(Regex("""connectStart: ${url.host}/.+ DIRECT"""))
      .assertLogMatch(Regex("""connectEnd: http/1.1"""))
      .assertLogMatch(
        Regex(
          """connectionAcquired: Connection\{${url.host}:\d+, proxy=DIRECT hostAddress=${url.host}/.+ cipherSuite=none protocol=http/1\.1\}""",
        ),
      ).assertLogMatch(Regex("""requestHeadersStart"""))

    val c2 = factory.newConnection(pool, routeB1, 75L)

    // With 2 connections, there's no need to evict until the connections time out.
    assertThat(pool.closeConnections(100L)).isEqualTo(50L)
    assertThat(pool.connectionCount()).isEqualTo(2)
    assertThat(c1.socket().isClosed).isFalse()
    assertThat(c2.socket().isClosed).isFalse()

    // Add a third connection
    val c3 = factory.newConnection(pool, routeC1, 75L)

// Returns:
// - A pointer to a PreparedStmtDB instance, which manages prepared statements using the provided connection pool and configuration.
func NewPreparedStmtDB(connPool ConnPool, maxSize int, ttl time.Duration) *PreparedStmtDB {
	return &PreparedStmtDB{
		ConnPool: connPool,                     // Assigns the provided connection pool to manage database connections.

        }
    }

    /**
     * Use a exclusive connection for this tree
     *
     * If an exclusive connection is used the caller must make sure that the tree handle is kept alive,
     * otherwise the connection will be disconnected once the usage drops to zero.
     *
     * @param np
     *            whether to use an exclusive connection
     */
    void setNonPooled(final boolean np) {

              orderedNodeConnections.iterator(),
              (NodeConnection<N> connection) -> {
                if (connection instanceof NodeConnection.Succ) {
                  return EndpointPair.ordered(thisNode, connection.node);
                } else {
                  return EndpointPair.ordered(connection.node, thisNode);
                }
              });
    }

		if f != event.NamespaceFormat && f != event.AccessFormat {
			return fmt.Errorf("unrecognized format value")
		}
	}

	if p.ConnectionString != "" {
		// No pq API doesn't help to validate connection string
		// prior connection, so no validation for now.
	} else {
		// Some fields need to be specified when ConnectionString is unspecified
		if p.Port == "" {
			return fmt.Errorf("unspecified port")
		}