getMetaType abstract method
Extracts the metadata type from a raw Meta map.
Retrieves the type identifier (e.g., "btc", "eth") from a raw Meta map with a fallback default value if the type field is missing.
@param meta - Raw Meta map containing type metadata
@param defaultValue - Fallback value if type is not found
@return Extracted Meta type (or defaultValue if not present)
Implementation
String? getMetaType(Mapping meta, [String? defaultValue]);