fix: multipart boundary does not meet the RFC (#61)
fix: multipart boundary does not meet the RFC (#61)

https://www.w3.org/Protocols/rfc1341/7_2_Multipart.html

boundary := 0*69<bchars> bcharsnospace 

bchars := bcharsnospace / " " 

bcharsnospace :=    DIGIT / ALPHA / "'" / "(" / ")" / "+"  / 
"_" 
               / "," / "-" / "." / "/" / ":" / "=" / "?"
ivanprjcts/sdklib,ivanprjcts/sdklib