I am trying to understand, how the string "100000000.000 SYS" is serialized into
struct asset from
eosio.token example (
cleos push action eosio.token create '[ "eosio", "1000000000.0000 SYS", 0, 0, 0]' -p eosio.token).
Is it built in functionality, or I can define my own custom structure which will be recognized by abi serializer, so I can communicate with my contract like it is done in eosio.token?