51bd01b3dd3d68c1628d74be9dc6d0f1cf1f15fe fix(file_store): recover file offset after read (志宇)
66dc34e75ab1ec2ae533bd540327721f6226eca1 refactor(file_store): Use BufReader but simplify (LLFourn)
c8717646700bdac0f1e13ec499481bd1fee30ffd test(file_store): `last_write_is_short` (志宇)
a3aa8b6682a3a13958fd5fbadc4074a1907a78db feat(file_store)!: optimize `EntryIter` by reducing syscalls (志宇)
Pull request description:
### Description
`EntryIter` performance is improved by reducing syscalls. The underlying file reader is wrapped with `BufReader` (to reduce calls to `read` and `seek`).
Two new tests are introduced. One ensures correct behavior when the last changeset write is too short. The other ensures the next write position is correct after a short read.
### Notes to the reviewers
This is extracted from #1172 as suggested by https://github.com/bitcoindevkit/bdk/pull/1172#pullrequestreview-1817465627.
### Changelog notice
Changed
* `EntryIter` performance is improved by reducing syscalls.
### Checklists
#### All Submissions:
* [x] I've signed all my commits
* [x] I followed the [contribution guidelines](https://github.com/bitcoindevkit/bdk/blob/master/CONTRIBUTING.md)
* [x] I ran `cargo fmt` and `cargo clippy` before committing
#### New Features:
* [x] I've added tests for the new feature
* [x] I've added docs for the new feature
ACKs for top commit:
LLFourn:
ACK 51bd01b3dd3d68c1628d74be9dc6d0f1cf1f15fe
Tree-SHA512: 9c25f9f2032cb2d551f3fe4ac62b856ceeb69a388f037b34674af366c55629a2eaa2b90b1ae4fbd425415ea8d02f44493a6c643b4b1a57f4507e87aa7ade3736
07116df541