public final HttpAsyncClientBuilder evictIdleConnections(final TimeValue maxIdleTime) {
        this.evictIdleConnections = true;
        this.maxIdleTime = maxIdleTime;
        return this;
    }
Makes this instance of HttpClient proactively evict idle connections from the
connection pool using a background thread.
<p>
One MUST explicitly close HttpClient with {@link CloseableHttpAsyncClient#close()}
in order to stop and release the background thread.
<p>
Please note this method has no effect if the instance of HttpClient is configured to
use a shared connection manager.

@see #setConnectionManagerShared(boolean)
@see ConnPoolControl#closeIdle(TimeValue)

@param maxIdleTime maximum time persistent connections can stay idle while kept alive
in the connection pool. Connections whose inactivity period exceeds this value will
get closed and evicted from the pool.

@return this instance.
httpclient5/src/main/java/org/apache/hc/client5/http/impl/async/HttpAsyncClientBuilder.java