/**
 * Returns a new channel, which flattens the terminal value of this channel.
 * This function may only be called if the terminal value of this channel is
 * another channel of compatible types.
 *
 * @tsplus getter effect/core/stream/Channel flatten
 */
export function flatten<
  Env,
  InErr,
  InElem,
  InDone,
  OutErr,
  OutElem,
  Env1,
  InErr1,
  InElem1,
  InDone1,
  OutErr1,
  OutElem1,
  OutDone2
>(
  self: Channel<
    Env,
    InErr,
    InElem,
    InDone,
    OutErr,
    OutElem,
    Channel<Env1, InErr1, InElem1, InDone1, OutErr1, OutElem1, OutDone2>
  >
): Channel<
  Env | Env1,
  InErr & InErr1,
  InElem & InElem1,
  InDone & InDone1,
  OutErr | OutErr1,
  OutElem | OutElem1,
  OutDone2
> {
  return self.flatMap(identity)
}