@abstract Superclass for all nvim remote objects.
@see Buffer @see Window @see Tabpage
Extend +==+ to only look at class and index.
Intercept method calls and delegate to appropriate RPC methods.
Extend methods to include RPC methods
Extend +respond_to?+ to support RPC methods.
Serialize object to MessagePack.
@param packer [MessagePack::Packer] @return [String]
[Validate]