public int consumeContent(ContentDecoder decoder) throws IOException
Reads content from the given ContentDecoder  and stores it in
this buffer.

 public int read() throws IOException
Reads one byte from this buffer. If the buffer is empty this method can
throw a runtime exception. The exact type of runtime exception thrown
by this method depends on implementation. This method returns 
-1 if the end of content stream has been reached.

 public int read(byte[] b,
    int off,
    int len) throws IOException
Reads up to len bytes of data from this buffer into
an array of bytes. The exact number of bytes read depends how many bytes
are stored in the buffer.

 If off is negative, or len is negative, or
off+len is greater than the length of the array
b, this method can throw a runtime exception. The exact type 
of runtime exception thrown by this method depends on implementation. 
This method returns -1 if the end of content stream has been 
reached.

 public  void reset()
Resets the buffer by clearing its state and stored content.