Fixing red bars at top of flame profile

Sorry just to clarify for the first suggestion I meant something like

struct FeatSpec{T}
    name::String                    # string version of name
    tuple::Tuple#{Vararg{UInt8}}     # tuple version of name
    id::UInt32                      # id in main featSpecList
    coreF::T                 # function that returns feature from specified granular segment
...<snipped>
end

const FeatValTypes::Type = Union{UInt8, Int8, String, Vector{UInt8}, Vector{Int8},Vector{String}}
 .... <snipped>

 vals0::FeatValTypes = f.coreF(docSens, s, t)

But it does sound like FunctionWrappers.jl would be the right choice here.