A record never starts within the last six bytes of a block (since it
won't fit). Any leftover bytes here form the trailer, which must
-consist entirely of zero bytes and must be skipped by readers.
+consist entirely of zero bytes and must be skipped by readers.
Aside: if exactly seven bytes are left in the current block, and a new
non-zero length record is added, the writer must emit a FIRST record
FIRST, MIDDLE, LAST are types used for user records that have been
split into multiple fragments (typically because of block boundaries).
FIRST is the type of the first fragment of a user record, LAST is the
-type of the last fragment of a user record, and MID is the type of all
-interior fragments of a user record.
+type of the last fragment of a user record, and MIDDLE is the type of
+all interior fragments of a user record.
Example: consider a sequence of user records:
A: length 1000