@Nonnull
	protected MappingKey getVariableKey(@Nonnull String className, @Nonnull String methodName, @Nonnull String methodDesc,
	                                    @Nullable String name, @Nullable String desc, int index) {
		return new VariableMappingKey(className, methodName, methodDesc, name, desc);
	}
@param className
		Class defining the method.
@param methodName
		Name of method.
@param methodDesc
		Type descriptor of method.
@param name
		Name of variable.
@param desc
		Type descriptor of variable.
@param index
		Local variable table index.

@return Key format for variable.
recaf-core/src/main/java/software/coley/recaf/services/mapping/MappingsAdapter.java