Unexpected `sizeof` struct with long StaticArrays

General Usage
2

The following seems to work for me

using StaticArrays

struct Dummy
    B::SVector{34,UInt8}
end
@assert sizeof(Dummy) == sum(sizeof.(fieldtypes(Dummy)))

struct Dummy32
    A::Float32
    B::SVector{32,UInt8}
end
@assert sizeof(Dummy32) == sum(sizeof.(fieldtypes(Dummy32)))

struct Dummy34
    A::Float32
    B::SVector{34,UInt8}
end

dummy1 = Dummy34(0.0, SVector((0 for _ in 1:34)...))
open("test.dat", "w") do fp
    write(fp, Ref(dummy1))
    @show position(fp) # --> 40
end

open("test.dat", "r") do fp
    dummy2 = Ref{Dummy34}()
    read!(fp, dummy2)
    @show position(fp) # --> 40
    @assert dummy2[] == dummy1
end

Regarding the size of Dummy34: I could imagine some kind of 32 bit alignment.