https://learn.microsoft.com/en-us/dotnet/api/system.reflection.emit.opcodes.stobj?view=netframework-4.8.1&redirectedfrom=MSDN
OpCodes.Stobj Field (System.Reflection.Emit) | Microsoft Learn
Copies a value of a specified type from the evaluation stack into a supplied memory address.
field systemopcodesreflectionemitmicrosoft