Hello,World!,Add,new,line.,Ok.,Substring,allocates,a,new,string,object,on,the,heap,and,performs,a,full,copy,of,the,extracted,text.String,manipulation,is,a,performance,bottleneck,for,many,programs.,Many,APIs,that,accept,strings,also,have,overloads,that,accept,a,ReadOnlySpan<System.Char>,argument.When,such,overloads,are,available,,you,can,improve,performance,by,calling,AsSpan,instead,of,Substring.