I working on "value for value" payments for podcasts using bitcoin lightning payments.
There is a standard for adding metadata to this payments, which is defined here: https://github.com/satoshisstream/satoshis.stream/blob/main/TLV_registry.md#field-7629169 (Key 7629169).
Now, I’d like to estimate how much space is left for the
extension section of the lightning message (as defined in BOLT #1), given that the maximum size of the total message is 2^16 bytes (65536).
Is there a reasonable way of doing this estimation?