getCmd abstract method
Retrieves the command name from a structured command content Map.
Looks up the command name key (e.g., "command")
in the content Map and returns its value. If the key is not found or the value
is null, returns the defaultValue (if provided).
Parameters:
content: The structured command payload (Map) to extract the command name fromdefaultValue: Optional fallback value if the command name is not found
Returns: Extracted command name (String), or defaultValue, or null if neither exists
Implementation
String? getCmd(Mapping content, [String? defaultValue]);