Ideally, upward, downward and lateral communication channels have people on both ends who are sensitive to issues created by timing. One of the roles of a leader in some organizations is to model desired behavior and develop productive habits throughout the team.
Since there are many more lateral communication channels within a team and there is an aspect of being a technical lead that is being a peer to the team's members [and not "the boss"], there is more productivity to be gained when all team members communicate in ways that reflect awareness of the state of the communication channel from the other person's perspective.
The problem with the internet text boxes is that complex human interactions get sketched and lose important details.
Since there are many more lateral communication channels within a team and there is an aspect of being a technical lead that is being a peer to the team's members [and not "the boss"], there is more productivity to be gained when all team members communicate in ways that reflect awareness of the state of the communication channel from the other person's perspective.
The problem with the internet text boxes is that complex human interactions get sketched and lose important details.