Allow for sending data

[LVala]

Additionally, modify the examples to create a media loop (browser -> Elixir PeerConnection -> browser).

[codecov[bot]]

Codecov Report

Merging #21 (0d0a0f7) into master (16043e7) will decrease coverage by 4.27%. The diff coverage is 47.88%.

:exclamation: Current head 0d0a0f7 differs from pull request most recent head e8cef4e. Consider uploading reports for the commit e8cef4e to get more accurate results

Additional details and impacted files

```diff @@ Coverage Diff @@ ## master #21 +/- ## ========================================== - Coverage 84.05% 79.78% -4.27% ========================================== Files 10 10 Lines 483 475 -8 ========================================== - Hits 406 379 -27 - Misses 77 96 +19 ``` | [Files](https://app.codecov.io/gh/elixir-webrtc/ex_webrtc/pull/21?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=elixir-webrtc) | Coverage Δ | | |---|---|---| | [lib/ex\_webrtc/media\_stream\_track.ex](https://app.codecov.io/gh/elixir-webrtc/ex_webrtc/pull/21?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=elixir-webrtc#diff-bGliL2V4X3dlYnJ0Yy9tZWRpYV9zdHJlYW1fdHJhY2suZXg=) | `100.00% <100.00%> (ø)` | | | [lib/ex\_webrtc/rtp\_transceiver.ex](https://app.codecov.io/gh/elixir-webrtc/ex_webrtc/pull/21?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=elixir-webrtc#diff-bGliL2V4X3dlYnJ0Yy9ydHBfdHJhbnNjZWl2ZXIuZXg=) | `92.30% <100.00%> (-0.29%)` | :arrow_down: | | [lib/ex\_webrtc/dtls\_transport.ex](https://app.codecov.io/gh/elixir-webrtc/ex_webrtc/pull/21?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=elixir-webrtc#diff-bGliL2V4X3dlYnJ0Yy9kdGxzX3RyYW5zcG9ydC5leA==) | `80.00% <42.10%> (-5.37%)` | :arrow_down: | | [lib/ex\_webrtc/peer\_connection.ex](https://app.codecov.io/gh/elixir-webrtc/ex_webrtc/pull/21?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=elixir-webrtc#diff-bGliL2V4X3dlYnJ0Yy9wZWVyX2Nvbm5lY3Rpb24uZXg=) | `72.41% <48.00%> (-7.38%)` | :arrow_down: | ... and [1 file with indirect coverage changes](https://app.codecov.io/gh/elixir-webrtc/ex_webrtc/pull/21/indirect-changes?src=pr&el=tree-more&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=elixir-webrtc) ------ [Continue to review full report in Codecov by Sentry](https://app.codecov.io/gh/elixir-webrtc/ex_webrtc/pull/21?src=pr&el=continue&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=elixir-webrtc). > **Legend** - [Click here to learn more](https://docs.codecov.io/docs/codecov-delta?utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=elixir-webrtc) > `Δ = absolute (impact)`, `ø = not affected`, `? = missing data` > Powered by [Codecov](https://app.codecov.io/gh/elixir-webrtc/ex_webrtc/pull/21?src=pr&el=footer&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=elixir-webrtc). Last update [16043e7...e8cef4e](https://app.codecov.io/gh/elixir-webrtc/ex_webrtc/pull/21?src=pr&el=lastupdated&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=elixir-webrtc). Read the [comment docs](https://docs.codecov.io/docs/pull-request-comments?utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=elixir-webrtc).