About MessagePackObject for getting Key value

[KWINEKO]

dump by Il2CppInspectorRedux

namespace ParipariApi.Shared.Models.Campaigns
{
	[MessagePackObject(false)]
	public class CampainBonusMaster // TypeDefIndex: 13911
	{
		// Properties
		[Key(0)]
		public long? CharacterGroupMasterId { get; set; } // 0x0000000180691070-0x0000000180691080 0x00000001806910B0-0x00000001806910C0
		[Key(1)]
		public CampaignBonusTypes CampaignBonusType { get; set; } // 0x00000001806824F0-0x0000000180682500 0x00000001806A7790-0x00000001806A77A0
		[Key(2)]
		public int CampaignBonusValue { get; set; } // 0x00000001806A76F0-0x00000001806A7700 0x00000001806A7730-0x00000001806A7740
		[Key(3)]
		public long? MonsterGroupMasterId { get; set; } // 0x0000000180A73150-0x0000000180A73160 0x0000000180C38110-0x0000000180C38120
	
		// Constructors
		public CampainBonusMaster() {} // 0x000000018066F110-0x000000018066F120
	}
}

I want to get the Key value of the MessagePackObject.
But I don't know how to get them(the Attributes of Properties).

    const mscorlib = Il2Cpp.domain.assembly('mscorlib').image

    const FieldInfo = mscorlib.class('System.Reflection.FieldInfo');

    function handleklass(klass:Il2Cpp.Class) {
        klass.fields.filter(
            field => field.name.endsWith('k__BackingField')
        ).forEach(field => {
            const RuntimeFieldHandle = mscorlib.class(
                'System.RuntimeFieldHandle').alloc()
            RuntimeFieldHandle.method('.ctor').invoke(field.handle)
            
            console.log(RuntimeFieldHandle.method('GetHashCode').invoke())

            const fieldInfo = FieldInfo.method(
                'GetFieldFromHandle', 1
            ).invoke(RuntimeFieldHandle)

I tried to get fieldInfo using the method get_Attributes,
but got error when using the method GetFieldFromHandle.

type: error
description: il2cpp: an unexpected native invocation exception occurred, this is due to parameter types mismatch
stack: il2cpp: an unexpected native invocation exception occurred, this is due to parameter types mismatch
    at invokeRaw (il2cpp/structs/method.ts:237)
    at invoke (il2cpp/structs/method.ts:217)
    at <anonymous> (.agent/debug.ts:38)
    at forEach (native)
    at handleklass (.agent/debug.ts:65)
    at <anonymous> (.agent/debug.ts:73)
    at forEach (native)
    at <anonymous> (.agent/debug.ts:73)
    at perform (il2cpp/perform.ts:15)
fileName: utils/console.ts
lineNumber: 3
columnNumber: 1

[KWINEKO]

I solved it

const properties = klass.type.object.method<Il2Cpp.Array<Il2Cpp.Object>>('GetProperties', 0).invoke()
for (var i = 0; i < properties.length; i++) {
            const propertie = properties.get(i)
            const attributes = propertie.method<Il2Cpp.Array<Il2Cpp.Object>>('GetCustomAttributes').invoke(true)
            for (var j = 0; j < attributes.length; j++) {
                const attribute = attributes.get(j)
                if (attribute.toString() != 'MessagePack.KeyAttribute') continue