ode>Stream</code> using the given mapper, then
subscribes to each new stream one after the next until all values are
emitted.</p>
<p>ConcatMap is similar to flatMap, but ensures order by guaranteeing that
all items from the created stream will be emitted before moving to the
next created stream. This process continues until all created streams have
completed.</p>
<p>This is a simple alias for Dart Stream's <code>asyncExpand</code>, but is included to
ensure a more consistent Rx API.</p>
<h3 id="example">Exa