issue with concatenated bgzip

[rulixxx]

Hitting error when analysing a bgzip BED that has been concatenated.

test_390_JI.bed.gz
test_389_JI.bed.gz

In bash:
cat test_389_JI.bed.gz test_390_JI.bed.gz > test_JI.bed.gz
tabix -p bed test_JI.bed.gz

In Julia:

using GenomicFeatures
using BGZFStreams

JI_bed_reader = BED.Reader(BGZFStream("./test_JI.bed.gz"),
           index = "./test_JI.bed.gz.tbi")

for i in eachoverlap(JI_bed_reader, Interval("chr6", 61374400, 61374500))
           println(i)
       end

ERROR: ArgumentError: too large in-block offset
Stacktrace:
 [1] seek(::BGZFStream{IOStream}, ::VirtualOffset) at /nfs/users/nfs_r/ra11/.julia/packages/BGZFStreams/qApsr/src/bgzfstream.jl:225
 [2] done(::GenomicFeatures.Indexes.TabixOverlapIterator{GenomicFeatures.BED.Reader}, ::GenomicFeatures.Indexes.TabixOverlapIteratorState{GenomicFeatures.BED.Record}) at /nfs/users/nfs_r/ra11/.julia/packages/GenomicFeatures/VNoux/src/indexes/overlap.jl:46
 [3] iterate at /nfs/users/nfs_r/ra11/.julia/packages/GenomicFeatures/VNoux/src/indexes/overlap.jl:72 [inlined]
 [4] iterate(::GenomicFeatures.Indexes.TabixOverlapIterator{GenomicFeatures.BED.Reader}) at /nfs/users/nfs_r/ra11/.julia/packages/GenomicFeatures/VNoux/src/indexes/overlap.jl:35
 [5] top-level scope at ./REPL[5]:1

Expected Behavior

It shouldn't bring up that error. It should output intersected intervals just like tabix does.

tabix test_JI.bed.gz chr6:61374400-61374500

chr6	61374417	61374418	0,0,0,0,0,0,0,0,8,6,6,2,0,...
chr6	61374448	61374449	0,0,0,0,0,0,0,0,5,5,6,3,0,...

Current Behavior

produces the too large in-block offset error

Possible Solution / Implementation

Exclude the condition block.size = 0 & inblock_offset = 0 from the error check.

if inblock_offset ≥ block.size & inblock_offset > 0
   throw(ArgumentError("too large in-block offset"))
end