julia> using DataFrames, CSVFiles, FileIO

julia> df = DataFrame(a = [1,2,3], b = [4,5,6]);

julia> stream = IOBuffer();

julia> fileiostream = Stream(format"CSV", stream);

julia> save(fileiostream, df)

julia> load(fileiostream)
0x0 CSV file
Error showing value of type CSVFiles.CSVStream:
ERROR: MethodError: no method matching zero(::Type{Any})
Closest candidates are:
  zero(::Type{Union{Missing, T}}) where T at missing.jl:87
  zero(::Type{LibGit2.GitHash}) at /Users/osx/buildbot/slave/package_osx64/build/usr/share/julia/stdlib/v1.1/LibGit2/src/oid.jl:220
  zero(::Type{Pkg.Resolve.VersionWeights.VersionWeight}) at /Users/osx/buildbot/slave/package_osx64/build/usr/share/julia/stdlib/v1.1/Pkg/src/resolve/VersionWeights.jl:19
  ...
Stacktrace:
 [1] zero(::Type{Any}) at ./missing.jl:87
 [2] reduce_empty(::typeof(+), ::Type) at ./reduce.jl:227
 [3] reduce_empty(::typeof(Base.add_sum), ::Type) at ./reduce.jl:234
 [4] mapreduce_empty(::typeof(identity), ::Function, ::Type) at ./reduce.jl:251
 [5] _mapreduce(::typeof(identity), ::typeof(Base.add_sum), ::IndexLinear, ::Array{Any,1}) at ./reduce.jl:305
 [6] _mapreduce_dim at ./reducedim.jl:308 [inlined]
 [7] #mapreduce#548 at ./reducedim.jl:304 [inlined]
 [8] mapreduce at ./reducedim.jl:304 [inlined]
 [9] _sum at ./reducedim.jl:653 [inlined]
 [10] _sum at ./reducedim.jl:652 [inlined]
 [11] #sum#550 at ./reducedim.jl:648 [inlined]
 [12] sum(::Array{Any,1}) at ./reducedim.jl:648
 [13] #printtable#1(::Bool, ::Function, ::IOContext{REPL.Terminals.TTYTerminal}, ::TableTraitsUtils.TableIterator{NamedTuple{(),Tuple{}},Tuple{}}, ::String) at /Users/harry/.julia/packages/TableShowUtils/ImkA9/src/TableShowUtils.jl:43
 [14] printtable(::IOContext{REPL.Terminals.TTYTerminal}, ::TableTraitsUtils.TableIterator{NamedTuple{(),Tuple{}},Tuple{}}, ::String) at /Users/harry/.julia/packages/TableShowUtils/ImkA9/src/TableShowUtils.jl:7
 [15] show(::IOContext{REPL.Terminals.TTYTerminal}, ::CSVFiles.CSVStream) at /Users/harry/.julia/packages/CSVFiles/KysmQ/src/CSVFiles.jl:38
 [16] show(::IOContext{REPL.Terminals.TTYTerminal}, ::MIME{Symbol("text/plain")}, ::CSVFiles.CSVStream) at ./sysimg.jl:194
 [17] display(::REPL.REPLDisplay, ::MIME{Symbol("text/plain")}, ::Any) at /Users/osx/buildbot/slave/package_osx64/build/usr/share/julia/stdlib/v1.1/REPL/src/REPL.jl:131
 [18] display(::REPL.REPLDisplay, ::Any) at /Users/osx/buildbot/slave/package_osx64/build/usr/share/julia/stdlib/v1.1/REPL/src/REPL.jl:135
 [19] display(::Any) at ./multimedia.jl:287
 [20] #invokelatest#1 at ./essentials.jl:742 [inlined]
 [21] invokelatest at ./essentials.jl:741 [inlined]
 [22] print_response(::IO, ::Any, ::Any, ::Bool, ::Bool, ::Any) at /Users/osx/buildbot/slave/package_osx64/build/usr/share/julia/stdlib/v1.1/REPL/src/REPL.jl:155
 [23] print_response(::REPL.AbstractREPL, ::Any, ::Any, ::Bool, ::Bool) at /Users/osx/buildbot/slave/package_osx64/build/usr/share/julia/stdlib/v1.1/REPL/src/REPL.jl:140
 [24] (::getfield(REPL, Symbol("#do_respond#38")){Bool,getfield(REPL, Symbol("##48#57")){REPL.LineEditREPL,REPL.REPLHistoryProvider},REPL.LineEditREPL,REPL.LineEdit.Prompt})(::Any, ::Any, ::Any) at /Users/osx/buildbot/slave/package_osx64/build/usr/share/julia/stdlib/v1.1/REPL/src/REPL.jl:714
 [25] #invokelatest#1 at ./essentials.jl:742 [inlined]
 [26] invokelatest at ./essentials.jl:741 [inlined]
 [27] run_interface(::REPL.Terminals.TextTerminal, ::REPL.LineEdit.ModalInterface, ::REPL.LineEdit.MIState) at /Users/osx/buildbot/slave/package_osx64/build/usr/share/julia/stdlib/v1.1/REPL/src/LineEdit.jl:2273
 [28] run_frontend(::REPL.LineEditREPL, ::REPL.REPLBackendRef) at /Users/osx/buildbot/slave/package_osx64/build/usr/share/julia/stdlib/v1.1/REPL/src/REPL.jl:1035
 [29] run_repl(::REPL.AbstractREPL, ::Any) at /Users/osx/buildbot/slave/package_osx64/build/usr/share/julia/stdlib/v1.1/REPL/src/REPL.jl:192
 [30] (::getfield(Base, Symbol("##734#736")){Bool,Bool,Bool,Bool})(::Module) at ./client.jl:362
 [31] #invokelatest#1 at ./essentials.jl:742 [inlined]
 [32] invokelatest at ./essentials.jl:741 [inlined]
 [33] run_main_repl(::Bool, ::Bool, ::Bool, ::Bool, ::Bool) at ./client.jl:346
 [34] exec_options(::Base.JLOptions) at ./client.jl:284
 [35] _start() at ./client.jl:436

julia> stream = IOBuffer();

julia> fileiostream = Stream(format"CSV", stream);

julia> mark(stream)
0

julia> save(fileiostream, df)

julia> reset(stream)
0

julia> mark(stream)
0

julia> load(fileiostream)
3x2 CSV file
a │ b
──┼──
1 │ 4
2 │ 5
3 │ 6