title: Wait for multiple statements to execute with R2DBC
body: <p>I need to execute multiple statement with <strong>R2DBC</strong> but couldn't find useful DatabaseClient#<strong>inConnection</strong>* examples... So my function keeps getting out too early:</p>
  <pre><code>public Publisher&lt;Person&gt; groupStatements(DatabaseClient client, Person person) {
  // yes, I know that's harsh, but hey! so is JPA's @ElementCollection
  return client.sql(&quot;DELETE FROM persons_address WHERE person = :id&quot;)
      .bind(&quot;id&quot;, person.getId())
      .fetch().rowsUpdated()
      .map(deleted -&gt; {
          // now recreate every relationship
          GenericExecuteSpec statement = client.sql(&quot;INSERT INTO persons_address (person, address) VALUES (:person, :address)&quot;);
          person.getOfficePlaces().forEach(address -&gt; {
              statement
                  .bind(&quot;person&quot;, person.getId()).bind(&quot;address&quot;, address.getId())
                  .fetch().rowsUpdated()  // there we go AWOL
                  .subscribe(inserted -&gt; {
                      // logging here
                  });
          });
          return person;  //FIXME wait! need above grouped statements to complete
      });
  }
  </code></pre>
  <p>NB: I'm using H2 as a backend.
  Thanks for any information!</p>