@Override
  public ByteBuffer[] nioByteBuffers() {
    checkRefCount();
    return new ByteBuffer[] { this.buf };
  }
An implementation of ByteBuff where a single BB backs the BBI. This just acts as a wrapper over a
normal BB - offheap or onheap
hbase-common/src/main/java/org/apache/hadoop/hbase/nio/SingleByteBuff.java