changes in version 0.99.0 (2024-03-17)
+ version for submission to Bioconductor

changes in version 1.5.7 (2025-09-15)
+ optimizations to speed up runtime

changes in version 1.7.1 (2026-04-26)
+ bug fixes; updates to speed up runtime

changes in version 1.9.2 (2026-05-18)
+ rename metric to boundary density
+ include normalization for number of nearest neighbors
+ include optional composition adjustments
+ return local and sample-level boundary density metric

changes in version 1.9.4 (2026-07-20)
+ add library size normalization before spatial smoothing by default
+ add log2 transformation after spatial smoothing by default
+ accept optional precomputed size factors

changes in version 1.9.5 (2026-07-26)
+ simplify boundary density calculations