@Override
    public boolean next() throws IOException {
      // This is a hot method so extreme measures taken to ensure it is small and inlineable.
      // Checked by setting: -XX:+UnlockDiagnosticVMOptions -XX:+PrintInlining -XX:+PrintCompilation
      assertSeeked();
      positionThisBlockBuffer();
      return _next();
    }
Go to the next key/value in the block section. Loads the next block if necessary. If
successful, {@link #getKey()} and {@link #getValue()} can be called.
@return true if successfully navigated to the next key/value
hbase-server/src/main/java/org/apache/hadoop/hbase/io/hfile/HFileReaderImpl.java