-- Two most important diff array types are fully polymorphic
-- lazy boxed DiffArray:
DiffArray, -- = IOToDiffArray IOArray
-- ...and strict unboxed DiffUArray, working only for elements
-- of primitive types but more compact and usually faster:
DiffUArray, -- = IOToDiffArray IOUArray
-- Two most important diff array types are fully polymorphic
-- lazy boxed DiffArray:
DiffArray, -- = IOToDiffArray IOArray
-- ...and strict unboxed DiffUArray, working only for elements
-- of primitive types but more compact and usually faster:
DiffUArray, -- = IOToDiffArray IOUArray