default Result preAppend(ObserverContext<? extends RegionCoprocessorEnvironment> c, Append append,
    WALEdit edit) throws IOException {
    return preAppend(c, append);
  }
Called before Append.
<p>
Call CoprocessorEnvironment#bypass to skip default actions. If 'bypass' is set, we skip out on
calling any subsequent chained coprocessors.
<p>
Note: Do not retain references to any Cells in 'append' beyond the life of this invocation. If
need a Cell reference for later use, copy the cell and use that.
@param c      the environment provided by the region server
@param append Append object
@param edit   The WALEdit object that will be written to the wal
@return result to return to the client if bypassing default processing
hbase-server/src/main/java/org/apache/hadoop/hbase/coprocessor/RegionObserver.java