in src/metadata/Schema.jl [551:560]
function Base.getproperty(x::KeyValue, field::Symbol)
if field === :key
o = FlatBuffers.offset(x, 4)
o != 0 && return String(x, o + FlatBuffers.pos(x))
elseif field === :value
o = FlatBuffers.offset(x, 6)
o != 0 && return String(x, o + FlatBuffers.pos(x))
end
return nothing
end