Create 2021-08-10-TimeoutRMW&QoS.md (#346)

* Create 2021-08-10-TimeoutRMW&QoS.md

* Update _posts/2021-08-10-TimeoutRMW&QoS.md

Co-authored-by: Ralph Lange <ralph-lange@users.noreply.github.com>

* Update _posts/2021-08-10-TimeoutRMW&QoS.md

Co-authored-by: Ralph Lange <ralph-lange@users.noreply.github.com>

Co-authored-by: Ralph Lange <ralph-lange@users.noreply.github.com>

Author: mamerlan

_posts/2021-08-10-TimeoutRMW&QoS.md

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+---
+title: Timeout RMW & QoS in RCLC APIs 
+author: Maria Merlan
+---
+There are NEW APIs available to improve the usability and scope of micro-ROS:
+ 
+- The new [RCLC QoS API](https://github.com/ros2/rclc/pull/119/) allows users to set custom QoS to better adjust the use cases. 
+So far, users could only use default or best effort entities. Now, this API allows the user to set a whole rmw_qos_profile_t. All internal QoS available in RMW as well as the entities can be customized to adjust every use case.  
+The RCLC QoS API applies to all entities. 
+ 
+- The new [RMW timeout API](https://github.com/micro-ROS/rmw-microxrcedds/pull/153) helps the user to configure the publication time block time when using a reliable mode in micro-ROS.
+When a topic is published in reliable mode in the RMW of Micro XRCE-DDS, the XRCE-DDS session will be run during a default time-out before sending an error, in order to confirm that the messages arrive to the Agent. This default timeout used to be managed by a buit-time configurable parameter. 
+The new RMW API allows the user to set a specific value for the timeout parameter at run-time for each reliable publisher, meaning before publishing. 
+ 
+This brings advantages:	
+  - Users can control the blocking time of a reliable publication.
+  - Users can reinforce time constraints to adjust the behaviour to their use case, allowing to fine-tune the timing of micro-ROS publisher operations.
+ 
+These enhancements are in line with the strategy of improving usability and scope of micro-ROS. We thank the community and early adopters for their great insights that contribute to enhancing micro-ROS usability and to better focus real use cases. 
+ 
+ 
+