This function can be used to set the value of channel variables or dialplan functions. When setting variables, if the variable name is prefixed with '_', the variable will be inherited into channels created from the current channel If the variable name is prefixed with '__', the variable will be inherited into channels created from the current channel and all children channels. MSet behaves in a similar fashion to the way Set worked in 1.2/1.4 and is thus prone to doing things that you may not expect. For example, it strips surrounding double-quotes from the right-hand side (value). If you need to put a separator character (comma or vert-bar), you will need to escape them by inserting a backslash before them. Avoid its use if possible.