"Decode as" in sharkd-JSON-RPC-Request-Syntax through API

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Hi , Is there a way to use "Decode as" in sharkd-JSON-RPC-Request-Syntax through API ? I am looking into sharkd webshark APIs and I can dissect a pcap properly. for the reference , I am using https://wiki.wireshark.org/sharkd-JSO.... I need to decode frames as PFCP but currently the protocol is shown as UDP.

in wireshark frame protocols are coming as - [protocol in frame : sll:ethertype:ip:udp:pfcp] but for the same pcap and same frame its coming as [Protocols in frame: sll:ethertype:ip:udp:data] in webshark.

Do I need to set any particular preferences or is there any other way to achieve "decode as" functionality in webshark?