public final H2AsyncClientBuilder setDefaultConnectionConfig(final ConnectionConfig connectionConfig) {
        this.connectionConfigResolver = host -> connectionConfig;
        return this;
    }
Sets the same {@link ConnectionConfig} for all hosts.

@return this instance.
@since 5.2
httpclient5/src/main/java/org/apache/hc/client5/http/impl/async/H2AsyncClientBuilder.java