function Extract(
    AByteCount: Integer = -1
): string;

string - Data extracted from the buffer.

Extract is a String function used to retrieve data from the internal storage for the buffer as a Delphi String data type. 

AByteCount indicates the number of bytes requested from the internal storage for the buffer. 

When AByteCount contains -1, all values in the buffer indicated by Size are extracted from the buffer. 

The return value for the method is the byte values retrieved from the internal storage for the buffer. 

When AByteCount contains a positive non-zero value, Extract calls ExtractToBytes to retrieve the data from internal storage, and calls BytesToString to prepare the return value for the function. Values retrieved from the internal storage for the buffer are also removed from the buffer.