public final PoolingAsyncClientConnectionManagerBuilder setConnectionConfigResolver(
            final Resolver<HttpRoute, ConnectionConfig> connectionConfigResolver) {
        this.connectionConfigResolver = connectionConfigResolver;
        return this;
    }
Sets {@link Resolver} of {@link ConnectionConfig} on a per route basis.

@return this instance.
@since 5.2
httpclient5/src/main/java/org/apache/hc/client5/http/impl/nio/PoolingAsyncClientConnectionManagerBuilder.java