Reads data from a blob into a new string
Device + Agent
The number of bytes to read
String — the blob-sourced bytes as a string
This method reads the specified number of bytes from the blob and returns them as a new string.
Only those bytes up to the end the source blob are read; if the call asks for 256 bytes but the read/write pointer is 128 bytes from the end, the new string will be 128 characters long.