public void clearWarnings() {
      sqlwarn = null;
   }
Clears all the warnings reporeted for the <code>StreamingRowSetImpl</code>
object. After a call to this method, the <code>getWarnings</code> method
returns <code>null</code> until a new warning is reported for this
<code>StreamingRowSetImpl</code> object.
src/main/java/org/replicadb/rowset/StreamingRowSetImpl.java