Void pokeString(var Binary block, Int offset, String val)
block: The binary block
offset: The location to write to (starting from zero)
val: The String to write.
Poke the string val into the block, starting at offset offset. An OffsetOutOfRange exception will be thrown if it attempts to access a value outside the block. Note that the String will be stored in the block in UTF-8 encoding, not as raw Kaya chars, so you need to use Builtins::byteLength to determine how much space you need (and then add one for a terminating null byte).