mutable struct SSLContext <: IO
    data
    ptr::Ptr{Cvoid}

    function SSLContext()
        ssl_context = new()
	method = ccall((:TLS_server_method, libssl), Ptr{Cvoid}, ())
	ssl_context.ptr = ccall((:SSL_CTX_new, libssl), Ptr{Cvoid}, (Ptr{Cvoid},), method)
	# if ssl_context.ptr == 0
	# end
	ssl_context
    end
end

mutable struct SSLClient{T}
    rbio::Ptr{Cvoid}
    wbio::Ptr{Cvoid}
    context::SSLContext
    ssl::Ptr{Cvoid}
    io_on_read
    sock::T
    write_buf::Vector{UInt8}
    encrypt_buf::Vector{UInt8}

    function SSLClient(ctx::SSLContext, io::T) where T
        client = new{T}()
        client.context = ctx
        client.ssl = SSL_new(ctx)
        client.io_on_read = (data) -> nothing
        SSL_accept_state(client)
        set_bio!(client, bio_new(), bio_new())
        client.write_buf = UInt8[]
        client.encrypt_buf = UInt8[]
        client.sock = io
        client
    end
end