@SuppressWarnings("PMD.AvoidBranchingStatementAsLastInLoop")
  private String getContentTypeValue(Map<String, Collection<String>> headers) {
    for (val entry : headers.entrySet()) {
      if (!entry.getKey().equalsIgnoreCase(CONTENT_TYPE_HEADER)) {
        continue;
      }
      for (val contentTypeValue : entry.getValue()) {
        if (contentTypeValue == null) {
          continue;
        }
        return contentTypeValue;
      }
    }
    return null;
  }
Returns {@link ContentProcessor} for specific {@link ContentType}.

@param type a type for content processor search.
@return {@link ContentProcessor} instance for specified type or null.
form/src/main/java/feign/form/FormEncoder.java