29, or 0x1d is used as a marker to mean the log level and time delta
cannot fit in a single byte, and the time delta will be a varint
following the current byte.
Prior to this commit, 29 second deltas would be written as 0x1d
instead of 0x1d1d, which the parser interpreted as a hint to read the
next byte, causing the parser to become offset by one byte and all
following logs to be potentially corrupt.