use buffer in BatchView

[CarloLucibello]

fix #156

This covers only BatchView(...; collate=nothing), I'm not sure how collate=true and collate=false should interact with the buffer so I won't address that here.

[codecov-commenter]

Codecov Report

Merging #157 (661f09e) into main (2677a73) will increase coverage by 0.11%. The diff coverage is 100.00%.

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@@            Coverage Diff             @@
##             main     #157      +/-   ##
==========================================
+ Coverage   88.46%   88.57%   +0.11%     
==========================================
  Files          13       15       +2     
  Lines         598      604       +6     
==========================================
+ Hits          529      535       +6     
  Misses         69       69              

Impacted Files	Coverage Δ
src/batchview.jl	82.35% <100.00%> (+1.50%)	:arrow_up:

... and 2 files with indirect coverage changes