Raft::Log::Segment(T)

Byte range within this segment file occupied by the entry at index. Returns {offset, length}.

Underlying file descriptor. Exposed for future zero-copy senders (sendfile/splice/io_uring).

Push buffered writes to the kernel page cache, then flush page cache to the device. Called at Raft durability boundaries (see Node#propose, Node#handle_append_entries, etc.). Two syscalls (write + fsync) per call.