Header (kafka 2.8.1 API)

```
public interface Header
```
A Header is a key-value pair, and multiple headers can be included with the key, value, and timestamp in each Kafka message. If the value contains schema information, then the header will have a non-null schema.
This is an immutable interface.

Method Summary

All Methods Instance Methods Abstract Methods
Modifier and Type	Method	Description
`String`	`key()`	The header's key, which is not necessarily unique within the set of headers on a Kafka message.
`Header`	`rename(String key)`	Return a new `Header` object that has the same schema and value but with the supplied key.
`Schema`	`schema()`	Return the `Schema` associated with this header, if there is one.
`Object`	`value()`	Get the header's value as deserialized by Connect's header converter.
`Header`	`with(Schema schema, Object value)`	Return a new `Header` object that has the same key but with the supplied value.

- Method Detail
  - key
```
String key()
```
    The header's key, which is not necessarily unique within the set of headers on a Kafka message.
    
    Returns:
    
    the header's key; never null
  - schema
```
Schema schema()
```
    Return the Schema associated with this header, if there is one. Not all headers will have schemas.
    
    Returns:
    
    the header's schema, or null if no schema is associated with this header
  - value
```
Object value()
```
    Get the header's value as deserialized by Connect's header converter.
    
    Returns:
    
    the deserialized object representation of the header's value; may be null
  - with
```
Header with(Schema schema,
            Object value)
```
    Return a new Header object that has the same key but with the supplied value.
    
    Parameters:
    
    schema - the schema for the new value; may be null
    
    value - the new value
    
    Returns:
    
    the new Header; never null
  - rename
```
Header rename(String key)
```
    Return a new Header object that has the same schema and value but with the supplied key.
    
    Parameters:
    
    key - the key for the new header; may not be null
    
    Returns:
    
    the new Header; never null