Why not set tenant to "" in ListTasksParams$Builder?

[yuyu123-yuyu]

Hi, I found that in ListTasksParams$Builder, the tenant field is required to be nonNull.

a2a-java/spec/src/main/java/io/a2a/spec/ListTasksParams.java

Line 230 in 7bf82c6

statusTimestampAfter, includeArtifacts, Assert.checkNotNullParam("tenant", tenant));

Whereas in MessageSendParams, the builder sets the tenant field to "" if it is null.

a2a-java/spec/src/main/java/io/a2a/spec/MessageSendParams.java

Line 134 in 7bf82c6

tenant == null ? "" : tenant);

Why the difference?

Considering that the constructors of ListTasksParams also set the tenant field to "" when it is not specified, would it be possible to do the same for ListTasksParams$Builder as well?

Thanks!