Journalling daemon

- Allows multiple connections
- The data from multiple connections is bundled into large writes to the
  journal
- The journal files have a fixed maximum size.
- Writes past the end of the journal cause a system-wide sync and
  writing starts over at the start of the journal.

Design Decisions:

- Use 64-bit CRC as block check code:
  - MD4 is faster (!) than even a hand-tuned CRC on P2/P3/Celeron CPUs
    due to its use of unrolled math operations instead of a per-byte
    table lookup which causes CPU serialization.
  - MD4 is a longer check code, which theoretically makes collisions
    less likely.
  - However, a CRC is designed such that all N-1 bit and shorter errors
    are guaranteed to be detected, whereas cryptographic hash have no
    such guarantee.

- Include stream identifier meta-data with the stream

- Delay committing transactions for a fraction of a second
  - Committing a transaction takes much longer than just writing data.
  - The cost of committing one transaction cannot be reduced.
  - The cost of committing N transactions can be reduced to that of
    committing one transaction by doing all the commits simultaneously.
  - If multiple connections are active, it is likely that one of the
    other connections will complete its data after the first one
    completes.
  - By waiting a fraction of a second, the first commit is delayed
    slightly, but the cost of that commit may be amortized by other
    commits happening simultaneously.

- Uniform length-prefixed string format
  - Reduces complexity of file formats and protocols, compared to using
    multiple string formats, thereby reducing the complexity of the
    required code.

- Include incremental global record number in each record
  - On wrap-around, this protects against older records being considered as
    valid after newer ones.