I'm finding two permutations of DD_PROPAGATION_STYLE_INJECT string being used throughout the documentation and the code:
A. DD_PROPAGATION_STYLE_INJECT
B. DD_PROPAGATION_INJECT_STYLE

From the Ruby documentation, I expected this library to parse the environment variable in permutation A. However, this library uses permutation B.

Go documentation mentions the use of permutation A which is consistent with the dd-trace-go source code

What do you think about updating the code to use permutation A (that'll be consistent with the documentation and other languages)?

extraction env var uses the wrong ordering as well.