2. The method of claim 1 , wherein said copying tokens from the reader buffer to a scanner buffer when the scanner receives a notification that the tokens are to be overwritten in the reader buffer comprises: processing a signal received by the scanner, the signal associated specifically with a token, for each of a selected plurality of tokens stored in the reader buffer, and receiving the token into the scanner from the reader, based on the signal.
2. The method of claim 1 , wherein said copying tokens from the reader buffer to a scanner buffer when the scanner receives a notification that the tokens are to be overwritten in the reader buffer comprises: processing a signal received by the scanner, the signal associated specifically with a token, for each of a selected plurality of tokens stored in the reader buffer, and receiving the token into the scanner from the reader, based on the signal. 3. The method of claim 2 , further comprising: for each of the selected plurality of tokens, holding a pointer pointing to the respective token of the selected plurality of tokens, wherein the scanner is configured to hold the pointer; and receiving each token into the scanner from the reader based on processing the pointer to that token.