question: public FluxFirstEmitting < T > ambAdditionalSource ( Publisher < ? extends T > source ) { if ( array != null ) { int n = array . length ; @ SuppressWarnings ( "unchecked" ) Publisher < ? extends T > [ ] newArray = new Publisher [ n + 1 ] ; System . arraycopy ( array , 0 , newArray , 0 , n ) ; newArray [ n ] = source ; return new FluxFirstEmitting < > ( newArray ) ; } return null ; }
target:  Returns a new instance which has the additional source to be amb'd together with the current array of sources. <p> This operation doesn't change the current FluxFirstEmitting instance.