v0.2.0

Breaking Changes

• LogManager::checkpoint_to now has an additional parameter, wal: &WriteAheadLog. This is provided for convenience because it may be necessary
  to randomly access information in the WAL while performing a checkpointing
  operation.

Added

• LogPosition::serialize_to/LogPosition::deserialize_from provide methods
  for reading and writing a LogPosition from an arbitrary Write/Read
  implementor (respectively). This uses a fixed-length serialization with a
  length of LogPosition::SERIALIZED_LENGTH -- 16 bytes.

Changed

• WriteAheadLog::shutdown() now no longer requires all instances of
  WriteAheadLog to be dropped to succeed.

Fixed

• When the WAL recycles a segment file, the LogPosition returned is now
  correct. Previously, returned LogPositions would contain the segment file's
  old id, causing those positions to be unreadable.
• When reading from a LogPosition, if the data has not been flushed or
  synchronized to disk yet, the read will be blocked until the sync operation
  finishes.