STRling bin format:
STR: array[char, 3] format_version: int16 software_version: array[9, char] proportion_repeat: float32 min_mapping_quality: uint8 fragment_length_distribution: array[4096, uint32] sam_header_length: int32 sam_header: $sam_header_length n_reads: int32 reads: array[$n_reads, tread] # note that these are in msgpack format.