transport protocol: bulk data -> ostreambuf

[malachib]

I as a developer would like to provide an "input ostreambuf" to the transport mechanism so that arbitrary data received may effectively be piped into named ostreambuf

NOTES

Use cases might be:

• ostringstreambuf to build up a version number
• specialized OTA streambuf capable of directly receiving and responding to incoming OTA data
• a kind of double-buffer/pipe streambuf whose only job is to mediate between two tasks (i.e. like https://www.freertos.org/xMessageBufferCreate.html )