val chunkSize = source.readUtf8LineStrict().trim().toInt(16)
              if (chunkSize == 0) {
                readEmptyLine(source)
                break
              }
              chunkSizes.add(chunkSize)
              requestBodySink.write(source, chunkSize.toLong())
              readEmptyLine(source)
            }
          }

          else -> Unit // No request body.
        }
      }