The first available index of the store, starts with 1 @return value >= 1

Get log entries with index between {@code start} and {@code end} @param start, the start index of log entries @param end, the end index of log entries

Appends a log entry to store @param logEntry @return the last appended log index

Gets the log entry at the specified index @param index, starts from 1 @return the log entry or null if index >= {@code this.getFirstAvailableIndex()}

The start index of the log store, at the very beginning, it must be 1 however, after some compact actions, this could be anything greater or equals to