Add Length and Substring with firstIndex and length in StringBuilder
Add Length and Substring with firstIndex and length in StringBuilder


ncave/Fable,fable-compiler/Fable,ncave/Fable,fable-compiler/Fable,inosik/Fable,ncave/Fable,fable-compiler/Fable,inosik/Fable,fable-compiler/Fable,ncave/Fable,ncave/Fable,fable-compiler/Fable,ncave/Fable,ncave/Fable,fable-compiler/Fable,fable-compiler/Fable