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