protected void currentValueBuffer() throws IOException {
      if (!keyInit) {
        nextKeyBuffer();
      }
      currentValue.keyBuffer = currentKey;
      currentValue.clearColumnBuffer();
      currentValue.readFields(in);
      currentValue.inited = true;
    }
Read and return the next record length, potentially skipping over a sync
block.

@return the length of the next record or -1 if there is no next record
@throws IOException
ql/src/java/org/apache/hadoop/hive/ql/io/RCFile.java