Answer true if the stream supports moving backwards with #skip:.
Move the position forwards by anInteger places
Advance the receiver until we find a character that is not a separator. Answer false if we reach the end of the stream, else answer true; in this case, sending #next will return the first non-separator character (possibly the same to which the stream pointed before #skipSeparators was sent).
Move the current position to after the next occurrence of anObject and return true if anObject was found. If anObject doesn’t exist, the pointer is atEnd, and false is returned.
If there is a sequence of objects remaining in the stream that is equal to the sequence in aCollection, set the stream position just past that sequence and answer true. Else, set the stream position to its end and answer false.