
File format:
+-------------------+=====================+
| header (48 bytes) | data (dynamic size) |
+-------------------+=====================+

Data format:
+================+-------------------------------------+-------------------+...
| indexes (256k) | next index block position (8 bytes) | data (up to 64MB) |
+================+-------------------------------------+-------------------+...
^----------------------------- dynamic repeat -----------------------------^


Indexes format (fixed size):
+----------------------------------+------------------------------+...
| original seek position (8 bytes) | real seek position (8 bytes) |
+----------------------------------+------------------------------+...
^----------------------- repeat 16384 times ----------------------^

+ Each block of indexes (256k) is sorted.
+ Right after the index block there is a seek position to next index block.
+ Data contains plain data blocks, each is 4k bytes. No metadata here.
