@field n_targets number of reference sequences
@field target_name names of the reference sequences
@field target_len lengths of the referene sequences
@field n_targets number of reference sequences
@field target_name names of the reference sequences
@field target_len lengths of the referene sequences
@field hash hash table for fast name lookup
@field rg2lib hash table for @RG-ID -> LB lookup
@field l_text length of the plain text in the header
@field hash hash table for fast name lookup
@field rg2lib hash table for @RG-ID -> LB lookup
@field l_text length of the plain text in the header
/*! @typedef
@abstract Structure for one alignment covering the pileup position.
@field b pointer to the alignment
/*! @typedef
@abstract Structure for one alignment covering the pileup position.
@field b pointer to the alignment