How to write to buffer in VIPS file format?

[HuBandiT]

Greetings,

My first time using VIPS.

I am trying to write a VIPS image into a (memory) buffer in VIPS format, however I'm getting an error:

irb(main):035:0>  Vips::Image.black(100, 100).write_to_buffer ".vips"
C:/Ruby32-x64/lib/ruby/gems/3.2.0/gems/ruby-vips-2.2.0/lib/vips/operation.rb:228:in `build': vipssave_target: no filename associated with target (Vips::Error)
        from C:/Ruby32-x64/lib/ruby/gems/3.2.0/gems/ruby-vips-2.2.0/lib/vips/operation.rb:483:in `call'
        from C:/Ruby32-x64/lib/ruby/gems/3.2.0/gems/ruby-vips-2.2.0/lib/vips/image.rb:638:in `write_to_buffer'
        from (irb):35:in `<main>'
        from C:/Ruby32-x64/lib/ruby/gems/3.2.0/gems/irb-1.6.2/exe/irb:11:in `<top (required)>'
        from C:/Ruby32-x64/bin/irb:33:in `load'
        from C:/Ruby32-x64/bin/irb:33:in `<main>'

What would be the correct invocation?

Thank you in advance.