public void buildFixedConnectionPool(final Pool pool,
                                         final Builder builder) {
        if (pool.getMaxConnections() <= 0) {
            throw new IllegalArgumentException("Max Connections value must be strictly positive");
        }
        if (pool.getAcquireTimeout() < 0) {
            throw new IllegalArgumentException("Acquire Timeout value must be positive");
        }
        builder.maxConnections(pool.getMaxConnections())
                .pendingAcquireTimeout(Duration.ofMillis(pool.getAcquireTimeout()))
                .pendingAcquireMaxCount(-1);
    }
build fixed connection pool.

@param pool    connection pool params
@param builder connection provider builder
shenyu-spring-boot-starter/shenyu-spring-boot-starter-plugin/shenyu-spring-boot-starter-plugin-httpclient/src/main/java/org/apache/shenyu/springboot/starter/plugin/httpclient/HttpClientFactory.java