pub fn read(
  run: fn(io.Context) -> io.Promise(value),
) -> Read(value)

pub fn run_read(
  call: Read(value),
  context: io.Context,
) -> io.Promise(value)

pub fn run_write(
  call: Write(value),
  context: io.Context,
) -> io.Promise(value)

pub fn write(
  run: fn(io.Context) -> io.Promise(value),
) -> Write(value)