|  | @@ -55,6 +55,13 @@
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				|  |  |  extern id const kGRPCHeadersKey;
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				|  |  |  extern id const kGRPCTrailersKey;
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				|  |  |  
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				|  |  | +// The container of the request headers of an RPC conforms to this protocol, which is a subset of
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				|  |  | +// NSMutableDictionary's interface. It will become a NSMutableDictionary later on.
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				|  |  | +// The keys of this container are the header names, which per the HTTP standard are case-
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				|  |  | +// insensitive. They are stored in lowercase (which is how HTTP/2 mandates them on the wire), and
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				|  |  | +// can only consist of ASCII characters.
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				|  |  | +// A header value is a NSString object (with only ASCII characters), unless the header name has the
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				|  |  | +// suffix "-bin", in which case the value has to be a NSData object.
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				|  |  |  @protocol GRPCRequestHeaders <NSObject>
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				|  |  |  
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				|  |  |  @property(nonatomic, readonly) NSUInteger count;
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