Rtos API example

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+# Hello!
+We are an open source project of [ARM mbed](https://www.mbed.com). Contributions via [pull request](https://github.com/ARMmbed/ble/pulls), and [bug reports](https://github.com/ARMmbed/ble/issues) are welcome!
+
+Please submit your pull request to the `develop` branch of [this module](https://github.com/ARMmbed/ble/tree/develop). Commits to develop will be merge into the master branch at the time of the next release.
+
+# Contributor agreement
+For your pull request to be accepted, we will need you to agree to our [contributor agreement](https://developer.mbed.org/contributor_agreement/) to give us the necessary rights to use and distribute your contributions. (To click through the agreement create an account on mbed.com and log in.)