Iteration and `pairs` not consistent with `getindex` or `read`

[yha]

The values returned from iteration over an AbfFile (or over the result of pairs) don't match what you get from indexing. Instead the values are of the undocumented type AbfKey. This violates the contract of pairs, and arguably also of the AbstractDict interface:

using AlignedBinaryFormat

tmp = tempname()
abfopen(tmp, "w") do abf
    abf["k"] = rand(10)
end

abf = abfopen(tmp, "r")
v = abf["k"]
k1, v1 = first(abf)  # or `first(pairs(abf))`
@assert v === v1     # fails
typeof(v1)           # == AlignedBinaryFormat.AbfKey
@show v[1]
@show v1[1] # ERROR: MethodError: no method matching getindex(::AlignedBinaryFormat.AbfKey, ::Int64)

[m-wells]

version 0.7.0 closes this issue