TailFile reading from NFS may introduce NUL characters.

On NFS - unlike on a normal file system - we can have a file where the first chunk of bytes has not arrived yet but the second has - as some network packets can arrive out of order. In this case we get the second chunk and the first filled with NUL as a temporary value, until the real values arrive.

Solution: Add a boolean property by which the user can tell the processor to yield (and try again later) whenever it encounters a NUL character. Requires caution as a file that contains NUL characters on purpose would block the processor indefinitely.